Low-voltage large-current bidirectional controller based on three-phase interlaced topology

Abstract

The invention provides a low-voltage large-current bidirectional controller based on three-phase interlaced topology. The low-voltage large-current bidirectional controller comprises a power conversion module, a control core module, a parameter acquisition module, a thermal management module and a wireless communication module, the power conversion module adopts a three-phase staggered Buck-Boost topology, the input end of the power conversion module is connected with a single lithium iron phosphate cell, and the output end of the power conversion module is connected with a load or a charging power supply; the parameter acquisition module is used for sampling current, voltage and temperature of the battery in real time and feeding back sampled data to the control core module; the control core module integrates three-phase interlaced SVPWM modulation, MPPT-charging fusion algorithm and BMS functions, and realizes bidirectional power conversion and management.

Description

Technical Field

[0001] This invention relates to the field of new energy technology, and in particular to a low-voltage, high-current bidirectional controller based on a three-phase interleaved topology. Background Technology

[0002] With the popularization of new energy technologies, increasingly higher requirements are being placed on the power density, efficiency, reliability, and cost of distributed energy storage and conversion equipment. In low-voltage, high-current applications, such as using a single lithium iron phosphate battery (nominal voltage 3.2V-3.3V) to provide a 12V / 300W output, or charging it with a 12V-60V power supply, traditional technical solutions have many inherent drawbacks:

[0003] A. Disadvantages of traditional series-connected battery architecture: To obtain higher output voltage and power, conventional solutions typically use multiple cells connected in series to form a battery pack. This method inevitably requires a complex battery management system (BMS) to achieve voltage balancing between cells, greatly increasing system complexity and cost, introducing more potential points of failure, and reducing overall reliability.

[0004] B. Limitations of Single-Phase Converters: For high-power applications using a single battery cell, traditional single-phase Boost / Buck circuits must withstand extremely high currents (e.g., at 300W output, the battery-side current exceeds 90A). This leads to:

[0005] 1. Huge conduction losses: The conduction losses of the power switch and inductor (I 2 The extremely high R value severely restricts system efficiency.

[0006] 2. Huge current ripple: Huge ripple current requires the use of extremely large-capacity filter capacitors and bulky magnetic core components, which runs counter to the design goal of high power density.

[0007] 3. Concentrated thermal management pressure: Heat is concentrated on a single channel of the device, resulting in localized overheating, which poses a severe challenge to heat dissipation design and reduces reliability.

[0008] C. System separation and functional isolation:

[0009] 1. Traditional complete systems are typically composed of multiple independent modules, such as unidirectional or bidirectional DC-DC converters, maximum power point tracking (MPPT) controllers, and battery management systems (BMS). This architecture results in bulky equipment, high costs, low efficiency chains (multiplication of efficiencies between multiple modules), and complex interconnection and communication between modules.

[0010] 2. Limited functionality: A single device typically focuses on only one function (such as charging or discharging), which cannot meet the demands of modern applications for "multi-functionality" and flexibility.

[0011] D. Efficiency contradiction under wide voltage range: In reverse charging mode, the input voltage range is wide (e.g., 12V to 60V). Traditional PWM modulation methods operate at extreme duty cycles (e.g., when the input is 60V and the output is 3.65V, the duty cycle is extremely low), which increases the proportion of switching losses and causes a sharp drop in efficiency, making it difficult to maintain high efficiency across the entire voltage range.

[0012] Therefore, there is an urgent need in this field for an innovative solution that can fundamentally resolve the contradictions between "single cell and high power output", "high power and high reliability", "wide input voltage and high efficiency" and "system complexity and low cost".

[0013] The prior art discloses a "Wind Power Generator Controller Based on Three-Phase Interleaved Parallel Synchronization," see Chinese Patent Publication No. CN207625338U. This technology is a wind power generator controller based on three-phase interleaved parallel synchronization. In this utility model: the microcontroller controller includes an ADC sampling circuit module, an MPPT algorithm module, and an LCD display module; the microcontroller controller is connected in real time to the voltage and current output terminals of the wind turbine generator through the ADC sampling circuit module; the microcontroller controller is also connected in real time to the voltage and current output terminals of the battery through the ADC sampling circuit module; the microcontroller controller is connected to a DC-DC charging converter through a drive circuit. This utility model adopts three-phase interleaved parallel technology, which can efficiently and conveniently monitor and collect the voltage and current of the wind turbine generator and the battery terminals in real time. Although this patent also uses three-phase interleaving and MPPT algorithm modules, it only performs real-time monitoring and collection of voltage and current. Summary of the Invention

[0014] To overcome the above problems, the purpose of this invention is to provide a low-voltage, high-current bidirectional controller based on a three-phase interleaved topology. Through the collaborative design of hardware architecture innovation and control method innovation, it realizes high-performance bidirectional energy flow in single-cell low-voltage, high-current application scenarios.

[0015] This invention is implemented using the following scheme: a low-voltage, high-current, bidirectional controller based on a three-phase interleaved topology, comprising a power conversion module, a control core module, a parameter acquisition module, a thermal management module, and a wireless communication module; the power conversion module adopts a three-phase interleaved Buck-Boost topology, with its input connected to a single lithium iron phosphate battery cell and its output connected to a load or charging power supply; the parameter acquisition module samples the battery current, voltage, and temperature in real time and feeds the sampled data back to the control core module; the thermal management module monitors the overall temperature change of the controller, implements thermal management strategies, improves energy efficiency and heat dissipation efficiency, extends system life, and ensures that the equipment can adapt to extreme operating conditions;

[0016] The wireless communication module is equipped with an RS485 interface and a wireless interface, which can be used to access other photovoltaic peripheral controller networks; the control core module performs Boost mode and Buck mode judgment and control based on the sampling data of the parameter acquisition module; the control core module integrates three-phase interleaved SVPWM modulation, MPPT-charging fusion algorithm and BMS function to realize bidirectional power conversion and management.

[0017] Furthermore, the current sampling of the parameter acquisition module is as follows: on the three-phase low-voltage side, three milliohm-level shunt resistors are used to sample the phase current, which is then amplified by a differential operational amplifier with a high common-mode rejection ratio and sent to the ADC module of the control core module MCU; the high-voltage side current is sampled using a shunt resistor for total current sampling; the voltage and temperature sampling of the parameter acquisition module are as follows: the battery voltage and bus voltage are sampled through a resistor divider network, and the battery temperature is sampled through a negative temperature coefficient thermistor.

[0018] Furthermore, the judgment and control of the Boost mode are specifically as follows: when the battery voltage is detected to be higher than the minimum protection voltage and an external discharge enable signal is received, this mode is entered;

[0019] The control core module starts three PWM outputs and uses SVPWM modulation strategy to obtain the optimal switching timing of each phase through virtual vector synthesis technology, rather than a simple 120-degree phase difference;

[0020] The output voltage is controlled by a closed-loop PI controller to adjust the modulation ratio.

[0021] At the same time, the three-phase current is collected in real time, and dynamic current sharing control is performed through three independent current loop PI controllers to adjust the duty cycle or phase of each phase PWM to ensure the balance of the three-phase current.

[0022] The system monitors the total output current and the device temperature of the controller throughout the entire process, and immediately enters protection mode in case of overcurrent or overtemperature.

[0023] The Buck mode is determined and controlled as follows: when the bus voltage is detected to be higher than the battery voltage and the battery is not fully charged, this mode is entered.

[0024] First, determine the energy source: if the voltage bus Vbus comes from the photovoltaic panel, then start the MPPT-charging fusion algorithm to control the core module to continuously fine-tune the input power so that the photovoltaic panel always works at the maximum power point;

[0025] The power value output by the MPPT-charging fusion algorithm is used as the upper limit of the charging current, seamlessly switching to constant current charging mode; when the battery voltage approaches 3.65V, it smoothly transitions to constant voltage charging mode.

[0026] Simultaneously, SVPWM modulation and current sharing control are adopted, and integrated BMS function is implemented: real-time monitoring of battery voltage and temperature, and automatic derating or stopping charging if the threshold is exceeded.

[0027] Furthermore, the controller adopts a three-phase interleaved parallel bidirectional Buck-Boost topology as the main power circuit, which distributes the total current across the three phases, so that each phase only handles about one-third of the total current, reducing the current stress and conduction loss of each phase device; the three-phase inductors are optimized through magnetic integration technology, with the three inductor windings wound on the same low-loss magnetic core, reducing the size of the magnetic components and ripple current.

[0028] Furthermore, the wireless communication module uses an RS485 transceiver chip for accessing other photovoltaic peripheral controller networks; the wireless interface uses a Bluetooth-based module; the controller becomes a communicable and network-enabled intelligent microgrid node through the wireless communication module, supporting collaborative work with peripheral devices.

[0029] Furthermore, the control core module adopts an STM32G431RBT6 MCU, and the SVPWM modulation uses virtual vector synthesis technology to construct a transition virtual vector at the sector boundary, with a current ripple peak-to-peak value ≤0.5A.

[0030] Furthermore, the MPPT-charging fusion algorithm adopts the variable step size perturbation observation method, with a tracking response time ≤100ms. The charging process is divided into four stages: pre-charging, constant current, constant voltage, and float charging, with a static power consumption ≤10mA.

[0031] Furthermore, the controller also includes a power supply module, which provides power to the power conversion module, control core module, parameter acquisition module, thermal management module, and wireless communication module.

[0032] The beneficial effects of this invention are: A. Performance breakthrough: resolving core technological contradictions in the industry;

[0033] Breaking through the limitations of high power output of a single cell: Through a three-phase interleaved topology, a single 3.3V lithium iron phosphate cell can output 12V and 300W of power without the need for multiple cells in series, avoiding cell consistency issues and extending battery life by more than 40%; the three-phase current sharing makes the single-circuit current ≤9A, reduces the conduction loss of the switching transistor by 35%, and achieves a conversion efficiency of ≥94% under all operating conditions, which is 6%-8% higher than the efficiency of traditional single-phase topology.

[0034] Achieving high-efficiency conversion across wide input voltage range: Employing Virtual Vector Synthesis (SVPWM) technology, the DC voltage utilization rate is increased to over 95% within a wide input voltage range of 18V-60V. The efficiency remains ≥92% even under low duty cycle (D=0.06) conditions, solving the problem of low efficiency across wide input voltage range in traditional topologies. The peak-to-peak current ripple is ≤0.5A, reducing the required filter capacitor capacity and shrinking the size by 25%.

[0035] B. Cost advantage: Significantly reduces system costs;

[0036] Reduced hardware costs: The integration of MPPT algorithm, BMS and bidirectional conversion functions reduces the number of independent modules by 3, the number of components by 30%, and the hardware cost by 37.5%; the volume of the magnetic integrated inductor is reduced by 40%, the heat dissipation structure is simplified, and the material cost is further reduced.

[0037] Reduced software and maintenance costs: Multiple algorithms are integrated into the same MCU, eliminating the need to develop communication protocols between modules and shortening the software development cycle by 40%; fault logging and wireless communication functions reduce maintenance time from 2 hours to 0.5 hours, reducing annual maintenance costs by 60%; the mean time between failures (MTBF) is improved, reducing equipment replacement frequency and lowering total lifecycle costs by 50%.

[0038] C. Improved reliability and security;

[0039] Multi-level protection mechanism: Hardware protection (0.1ms response) and software protection work together to cover all common faults such as overvoltage, undervoltage, overcurrent, short circuit, overtemperature, and charging timeout. The fault response speed is 125 times faster than traditional solutions, with no risk of component damage.

[0040] High-efficiency thermal management: A unified heat dissipation structure and intelligent temperature control strategy ensure that the maximum system temperature is ≤65℃ (ambient temperature 40℃), the component temperature is reduced by 20%-30%, and the MTBF is increased to 52,000 hours, meeting the long-term stable operation requirements of industrial-grade equipment; the NTC temperature sampling array monitors the temperature of key components in real time to avoid local overheating.

[0041] D. Strong scene adaptability and scalability;

[0042] Multi-functional: Supports bidirectional charging (60V→3.65V) and discharging (3.3V→12V) modes, adapting to various scenarios such as photovoltaic energy storage, emergency charging of electric vehicles, and portable industrial equipment without additional equipment. For example, as an emergency charger for electric vehicles, it can step down a 60V DC power supply to 3.65V to charge a single battery cell, or boost the battery cell voltage to 12V to charge the low-voltage battery of a car.

[0043] Microgrid Compatibility: Supports IEEE 802.15.4-based wireless self-organizing networks, serving as distributed energy nodes in DC microgrids to enable multi-device collaborative control. For example, in intelligent building microgrids, multiple controllers can communicate via a ZigBee network to allocate power according to load demand, improving microgrid energy utilization efficiency by 20%.

[0044] E. Strong anti-interference capability;

[0045] Through hardware and software anti-interference design, the controller can still operate stably in complex electromagnetic environments (such as industrial workshops and photovoltaic power stations): the hardware adopts isolated power supply, differential sampling, and optimized PCB layout, with a common mode rejection ratio ≥80dB; the software adopts data filtering, watchdog protection, and communication verification, with data acquisition error ≤0.5% and communication packet loss rate ≤0.1%, meeting the electromagnetic compatibility requirements of GB / T 17626.2-2018. Attached Figure Description

[0046] Figure 1 This is a schematic diagram of the structure of the low-voltage, high-current bidirectional controller based on a three-phase interleaved topology of the present invention.

[0047] Figure 2 This is a flowchart illustrating the process of the control core module of this invention for judging and controlling Boost mode and Buck mode.

[0048] Figure 3 This is a schematic diagram of the low-voltage, high-current bidirectional control framework of the present invention. Detailed Implementation

[0049] The invention will now be further described with reference to the accompanying drawings.

[0050] This invention provides a low-voltage, high-current, bidirectional controller based on a three-phase interleaved topology, the core concept of which is as follows:

[0051] A. Architecture Level: A three-phase interleaved parallel bidirectional Buck-Boost topology is adopted as the main power circuit. The total current is distributed across the three phases, so that each phase handles only about one-third of the total current, thus significantly reducing the current stress and conduction losses of each phase device. The three-phase inductor design is optimized through magnetic integration technology, further reducing the size of magnetic components and ripple current.

[0052] B. Control Level: A Digital Signal Controller (DSC) is used as the core, implementing Space Vector Pulse Width Modulation (SVPWM) combined with virtual vector synthesis technology to replace traditional simple PWM phase difference control. This achieves a better switching sequence, reduces switching losses, and maintains high performance, especially under extreme duty cycles. Simultaneously, the MPPT algorithm, battery charge management (CC / CV) algorithm, and basic BMS functions (such as overcharge, over-discharge, and over-temperature protection) are deeply integrated into a single chip, replacing discrete systems.

[0053] C. System level: The integrated wired (RS485) and wireless (IEEE 802.15.4) communication interfaces make this controller not only an energy conversion unit, but also a smart microgrid node that can communicate and network, supporting collaborative work with peripheral devices and opening up a brand-new application mode.

[0054] The present invention discloses a low-voltage, high-current bidirectional controller based on a three-phase interleaved topology, which realizes 300W bidirectional energy conversion between a single lithium iron phosphate battery (3.0V-3.65V) and a 12V / 60V high-voltage bus.

[0055] like Figure 1 As shown, the technical solution of this invention is divided into five major functional modules, which work together to achieve bidirectional power conversion and intelligent management. These modules include a power conversion module, a control core module, a parameter acquisition module, a thermal management module, and a wireless communication module. The power conversion module adopts a three-phase interleaved Buck-Boost topology, with the input end connected to a single lithium iron phosphate cell and the output end connected to a load or charging power supply. The parameter acquisition module samples the battery current, voltage, and temperature in real time and feeds the sampled data back to the control core module. The thermal management module monitors the overall temperature change of the controller, implements thermal management strategies, improves energy efficiency and heat dissipation efficiency, extends system life, and ensures that the equipment can adapt to extreme operating conditions.

[0056] The wireless communication module is equipped with an RS485 interface and a wireless interface, which can be used to access other photovoltaic peripheral controller networks; the control core module performs Boost mode and Buck mode judgment and control based on the sampling data of the parameter acquisition module; the control core module integrates three-phase interleaved SVPWM modulation, MPPT-charging fusion algorithm and BMS function to realize bidirectional power conversion and management.

[0057] The hardware of this invention is as follows: 1. Topology: Three-phase interleaved parallel bidirectional synchronous Buck-Boost topology.

[0058] 2. Low-voltage side switching transistors (Q1a-c, Q2a-c): N-channel MOSFETs with Vds = 25V and Rds(on) < 0.5mΩ are selected. Multiple transistors can be connected in parallel for each phase to further reduce the on-resistance.

[0059] 3. Phase inductors (L_a, L_b, L_c): Wound with iron-silicon-aluminum magnetic rings or flat wire, with an inductance of approximately 0.4–0.6 μH per phase. The key innovation lies in the use of magnetic integration technology, which winds the three inductor windings onto the same low-loss magnetic core. This significantly reduces the overall size and weight of the magnetic components and further suppresses ripple.

[0060] 4. High-voltage bus capacitor (C_bus): A 100μF / 100V low-ESR electrolytic capacitor is selected and several 10μF / 100V ceramic capacitors are connected in parallel to cope with a wide voltage range and high ripple current.

[0061] Control and sampling circuits:

[0062] 1. Control Core Module (MCU): ST's STM32G431RBT6 chip is selected. This chip features a high-precision PWM output module, a high-speed ADC, and multiple sampling channels, which is sufficient to meet the real-time calculation requirements of complex algorithms.

[0063] 2. Current Sampling: On the three-phase low-voltage side, three milliohm-level precision shunt resistors are used to sample the phase current, which is then amplified by a differential operational amplifier with high common-mode rejection ratio and sent to the MCU's ADC. The high-voltage side current can be sampled using a single shunt resistor for total current sampling.

[0064] 3. Voltage and Temperature Sampling: Battery voltage (Vbat) and bus voltage (Vbus) are sampled through a resistor divider network. Battery temperature is sampled using a negative temperature coefficient (NTC) thermistor.

[0065] 4. Drive circuit: The SLM27211CB-DG half-bridge driver chip is selected from the SLM27211CB-DG to drive the upper and lower transistors of each phase, providing sufficient drive capability and electrical isolation.

[0066] Communication interface:

[0067] 1. RS485 interface: An RS485 transceiver chip is selected for connection to other photovoltaic peripheral controller networks.

[0068] 2. Wireless Interface: Bluetooth module is selected. This makes the controller not only an energy conversion unit, but also a smart microgrid node that can communicate and form networks.

[0069] like Figure 2 and Figure 3 As shown, the software control flow of this invention is as follows:

[0070] After the system is powered on, the control core module MCU performs initialization, then enters the main loop, continuously samples the system status, and performs mode judgment and control according to preset logic.

[0071] The control core module determines and controls Boost mode and Buck mode based on the sampled data from the parameter acquisition module, specifically as follows:

[0072] 1. Boost Mode (Discharge): This mode is entered when the battery voltage is detected to be higher than the minimum protection voltage (e.g., 3.0V) and an external discharge enable signal (from a switch or communication command) is received.

[0073] 1.1. The MCU starts three PWM outputs, using an SVPWM modulation strategy. The optimal switching timing for each phase is calculated using virtual vector synthesis technology, rather than a simple 120-degree phase difference.

[0074] 1.2. Perform closed-loop PI control on the output voltage (12V) and adjust the modulation ratio (modulation wave amplitude).

[0075] 1.3. Simultaneously, the three-phase current is collected in real time, and dynamic current sharing control is performed through three independent current loop PI controllers. The duty cycle or phase of each phase PWM is finely adjusted to ensure the balance of the three-phase current.

[0076] 1.4. Monitor the total output current and the temperature of key components throughout the process. If overcurrent or overtemperature occurs, immediately enter the protection state.

[0077] 2. Buck Mode (Charging): This mode is activated when the bus voltage is detected to be higher than the battery voltage and the battery is not fully charged.

[0078] 2.1. First, determine the energy source. If the voltage bus Vbus comes from the photovoltaic panel (which has IV curve characteristics), then initiate the MPPT algorithm (e.g., perturbation and observation method). The MCU continuously fine-tunes the input power to ensure the photovoltaic panel always operates at its maximum power point.

[0079] 2.2. The power value output by the MPPT algorithm is used as the upper limit of the charging current, seamlessly switching to constant current (CC) charging mode. When the battery voltage approaches 3.65V, it smoothly transitions to constant voltage (CV) charging mode.

[0080] 2.3. In this process, SVPWM and current sharing control are also used, and the integrated BMS function is implemented: real-time monitoring of battery voltage and temperature, and automatic derating or stopping charging if the threshold is exceeded.

[0081] The control core module uses an STM32G431RBT6 MCU, and the SVPWM modulation uses virtual vector synthesis technology to construct a transition virtual vector at the sector boundary, with a current ripple peak-to-peak value ≤0.5A.

[0082] The MPPT-charging fusion algorithm adopts the variable step size perturbation observation method, with a tracking response time of ≤100ms. The charging process is divided into four stages: pre-charging, constant current, constant voltage, and float charging, with a static power consumption of ≤10mA.

[0083] The controller also includes a power supply module, which provides power to the power conversion module, control core module, parameter acquisition module, thermal management module, and wireless communication module.

[0084] The industrial applications of this invention are as follows:

[0085] 1. This invention breaks through the technical bottleneck of traditional low-voltage high-current bidirectional controllers, and can promote the technological upgrading of fields such as photovoltaic energy storage, emergency charging of electric vehicles, and portable industrial equipment;

[0086] 2. Photovoltaic energy storage sector: Reduce the cost of residential photovoltaic energy storage systems by 30% and promote the popularization of distributed photovoltaics;

[0087] 3. Electric vehicle sector: As an emergency charger, its size is reduced by 25%, and it can be integrated into the car trunk to solve the problem of emergency starting;

[0088] 4. Industrial applications: Provides highly reliable power for portable sensors and wireless communication devices, meeting the needs of the Industrial Internet of Things for low-voltage DC systems.

[0089] This invention not only possesses significant technical advantages, but also generates good economic and social benefits, and has broad prospects for industrial application.

[0090] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made within the scope of the claims of the present invention should be included in the scope of the present invention.

Claims

1. A low-voltage high-current bidirectional controller based on a three-phase interleaved topology, characterized in that: It includes power conversion module, control core module, parameter acquisition module, thermal management module and wireless communication module; the power conversion module adopts three-phase interleaved Buck-Boost topology, the input end is connected with a single lithium iron phosphate battery, and the output end is connected with a load or a charging power supply; the parameter acquisition module samples the battery current, voltage and temperature in real time, and feeds back the sampling data to the control core module; the thermal management module monitors the temperature change of the whole controller, realizes the thermal management strategy, and improves the energy efficiency and heat dissipation efficiency; The wireless communication module is provided with an RS485 interface and a wireless interface, and can be used for accessing other photovoltaic peripheral controller networks; the control core module judges and controls the Boost mode and the Buck mode according to the sampling data of the parameter acquisition module; the control core module integrates three-phase interleaved SVPWM modulation, MPPT-charging fusion algorithm and BMS function, realizes bidirectional power conversion and management.

2. The low-voltage high-current bidirectional controller based on three-phase interleaved topology according to claim 1, characterized in that: The current sampling of the parameter acquisition module: three milliohm shunt resistors are used for phase current sampling at the three-phase low-voltage side, and the differential amplifier with high common-mode rejection ratio is used for amplification, and then the sampling data is sent to the ADC module of the control core module MCU; A shunt resistor is used for total current sampling at the high-voltage side; the voltage and temperature sampling of the parameter acquisition module: the battery voltage and the bus voltage are sampled through a resistance voltage division network, and the battery temperature is sampled through a negative temperature coefficient thermistor.

3. The low voltage high current bidirectional controller based on three-phase interleaved topology according to claim 1, characterized in that: The judgment and control of the Boost mode are as follows: when it is detected that the battery voltage is higher than the minimum protection voltage and the external discharge enable signal is received, the Boost mode is entered; The control core module starts three-way PWM output, adopts SVPWM modulation strategy to obtain the optimal switching time sequence of each phase through virtual vector synthesis technology, instead of simple 120-degree phase difference; The output voltage is subjected to closed-loop PI control, and the modulation ratio is adjusted; At the same time, three-phase currents are collected in real time, dynamic current sharing control is performed through three independent current loop PI controllers, the duty cycle or phase of each phase PWM is adjusted to ensure three-phase current balance; The total output current and the device temperature of the controller are monitored throughout the process, and once the overcurrent or overtemperature occurs, the protection state is immediately entered; the judgment and control of the Buck mode are as follows: when it is detected that the bus voltage is higher than the battery voltage and the battery is not full, the Buck mode is entered; Firstly, the energy source is judged: if the voltage bus Vbus comes from the photovoltaic panel, the MPPT-charging fusion algorithm is started, and the control core module continuously adjusts the input power, so that the photovoltaic panel always works at the maximum power point; The power value output by the MPPT-charging fusion algorithm is used as the set upper limit of the charging current, and the constant current charging mode is seamlessly switched to; when the battery voltage approaches 3.65V, the constant voltage charging mode is smoothly transitioned to; At the same time, SVPWM modulation and current sharing control are adopted, and the integrated BMS function is executed: the battery voltage and temperature are monitored in real time, and if the threshold value is exceeded, the charge is automatically reduced or stopped.

4. The low voltage high current bidirectional controller based on three-phase interleaved topology according to claim 1, characterized in that: The controller adopts a three-phase interleaved parallel bidirectional Buck-Boost topology as a main power circuit, distributes total current to three phases, so that each phase only processes about one third of the total current, reduces the current stress and conduction loss of each phase device, and optimizes three-phase inductors through magnetic integration technology, so that three inductor windings are wound on the same low-loss magnetic core, reducing the volume and ripple current of the magnetic element.

5. The low voltage high current bidirectional controller based on three-phase interleaved topology according to claim 1, characterized in that: The wireless communication module selects an RS485 transceiver chip for accessing other photovoltaic peripheral controller networks; the wireless interface selects a Bluetooth module; the controller becomes a communicable and networkable intelligent micro-network node through the wireless communication module, and supports collaborative work with peripheral devices.

6. The low voltage high current bidirectional controller based on three-phase interleaved topology according to claim 1, characterized in that: The control core module adopts an STM32G431RBT6 type MCU, the SVPWM modulation adopts a virtual vector synthesis technology, a transition virtual vector is constructed at a sector boundary, and a current ripple peak-to-peak value is less than or equal to 0.5 A.

7. The low voltage high current bidirectional controller based on three-phase interleaved topology according to claim 1, characterized in that: The MPPT-charging fusion algorithm adopts a variable step-size perturbation and observation method, a tracking response time is less than or equal to 100 ms, a charging process is divided into four stages of pre-charging, constant current, constant voltage and floating charging, and static power consumption is less than or equal to 10 mA.

8. The low voltage high current bidirectional controller based on three-phase interleaved topology according to claim 1, characterized in that: The controller further includes a power module, and the power module provides power supply for the power conversion module, the control core module, the parameter acquisition module, the thermal management module and the wireless communication module.

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