Solar charging controller with common-ground Bluetooth function

Abstract

The utility model discloses a solar charging controller with a common-ground Bluetooth function, which comprises a solar battery, a storage battery, a load LED (light-emitting diode), a central control MCU (microprogrammed control unit) Bluetooth communication module, a PWM (pulse-width modulation) charging module, a power management module, a flat voltage current limiting module, a voltage sampling module and an anti-backflow circuit, the negative electrode of the solar cell and the negative electrode of the storage battery are connected with a common ground GND, the flat voltage current limiting circuit comprises a power MOSFET circuit and a current sampling circuit, and the voltage sampling circuit comprises a solar cell voltage sampling circuit and a storage battery voltage sampling circuit. According to the utility model, PHY6212 is integrated with MCU and Bluetooth communication functions, so that the cost requirement is met, the previous hand-held remote controller is removed, and the operation is changed into the operation of the intelligent mobile phone by one hand, so that the operation is more convenient, simpler and more flexible, the OTA upgrade is realized, and the maintenance cost is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of solar charging, in particular to a solar charging controller with a common bluetooth function. Background Art

[0002] At present, there are many types of solar charge controllers on the market, most of which are charge controllers with a common positive electrode structure. There are some shortcomings in actual operation. In the charging circuit of some simple solar charge controllers, the battery is over-discharged for a long time due to some reasons, resulting in too low voltage. In order to protect the battery, the charging circuit is opened. At this time, the positive and negative poles of the solar panel may be short-circuited, which will cause the temperature of the solar panel array to be too high, which is easy to damage the solar panel and reduce the service life of the solar panel. Since the negative pole of the solar cell and the pole of the battery are not in common, it is difficult to sample the voltage of the solar cell. In the design of the anti-backflow circuit of some solar charge controllers, a diode is connected in series to prevent the battery current from flowing back to the solar cell at night. However, when charging, the forward conduction voltage drop of the diode is large, and the conduction loss is large, resulting in low conversion efficiency of the charge controller.

[0003] Most controllers use infrared communication and wireless 2.4G communication. The controller parameters are set and the current real-time parameters are read through a handheld remote control. The disadvantage of infrared communication is that the communication distance is short and it is greatly affected by sunlight during the day. After attenuation, the distance is only a few meters. The controller can only be controlled at night when placed on a light pole. 2.4G wireless communication has a long distance but high cost and low process reliability. Utility Model Content

[0004] The utility model aims to provide a solar charging controller with a common Bluetooth function, so as to solve the technical problems existing in the prior art.

[0005] To achieve the above-mentioned purpose, the utility model provides a solar charging controller with a common ground Bluetooth function, comprising a solar cell, a storage battery, a load LED, a central control MCU Bluetooth communication module, a PWM charging module, a power management module, a voltage leveling and current limiting module, a voltage sampling module, and also comprising an anti-backflow circuit, wherein the anti-backflow circuit is connected to the PWM drive circuit, the negative electrode of the solar cell and the negative electrode of the storage battery are connected to a common ground GND, the voltage leveling and current limiting circuit comprises a power MOSFET circuit and a current sampling circuit, and the voltage sampling circuit comprises a solar cell voltage sampling circuit and a battery voltage sampling circuit;

[0006] The solar charging controller with common Bluetooth function is used to control solar panels, batteries and loads. During the day, when the solar panels have voltage, the three-stage PWM charging method is used to charge the batteries, and the load is turned off at this time; at night, when the solar panels have no voltage, the load is turned on, and the battery voltage reaches the working voltage of the load through the voltage-smoothing module and performs current limiting output. At the same time, there is time period control to meet the user's various time period requirements.

[0007] Furthermore, the solar charging controller with the common Bluetooth function can directly drive LED street lights, and read and write parameters in the controller and perform OTA upgrades through a smartphone APP.

[0008] Furthermore, the MCU Bluetooth communication module uses the single-chip PHY6212 chip as the main chip, which has its own 6-bit AD channel and integrated Bluetooth communication function. It can realize system voltage sampling and import it into the control algorithm for calculation, and then output control signals to the entire solar charge and discharge controller system. It has an internal integrated Bluetooth function and adopts Bluetooth Mesh low-power technology. It can send parameters to the controller and read real-time parameters through a mobile phone APP to realize OTA upgrade.

[0009] Furthermore, the negative pole of the solar cell and the negative pole of the battery in the PWM charging module are connected to a common ground GND, and include a backflow prevention circuit and a PWM drive circuit, which control the solar panel to charge the battery according to a predetermined charging curve to avoid damage to the battery due to over-discharge, over-charge, and over-voltage. The MOS tube is controlled to perform PWM charging through the MOS tube drive circuit and the single-chip microcomputer instruction, and the battery is protected from over-discharge, over-charge, and over-voltage through the sampling circuit.

[0010] Furthermore, the battery management module provides MCU power supply, PWM drive voltage, and indicator light circuit power supply to monitor and protect the battery.

[0011] Furthermore, the voltage-smoothing and current-limiting circuit in the voltage-smoothing and current-limiting module includes a power MOSFET circuit and a current sampling circuit. The voltage-smoothing and current-limiting circuit is connected to the positive electrode of the solar cell, and the battery voltage is output to the load through the voltage-smoothing circuit. The battery voltage of a single string of lithium iron phosphate cells is 3.2V, and the output current range is 0-10A, but the power cannot exceed 30W.

[0012] Furthermore, the voltage sampling module collects the solar panel voltage and the battery voltage through resistor voltage division, the negative electrode of the solar cell and the negative electrode of the battery are connected to a common ground GND, and the solar cell voltage is collected through resistor voltage division.

[0013] The utility model has the following advantages:

[0014] 1. It has the function of self-checking the system when it is powered on for the first time, which can automatically detect the accuracy of the wiring sequence;

[0015] 2. Applicable to the occasions where the load working voltage is equal to the battery voltage;

[0016] 3. In the charging mode, the negative pole of the solar cell and the negative pole of the battery are connected to the common ground GND, which increases the service life of the solar panel, improves the conversion efficiency of the controller, and makes the solar cell voltage sampling more convenient.

[0017] 4. IP67 waterproof rating, excellent thermal balance design and natural air cooling, can be used in various harsh environments;

[0018] 5. Intelligent control mode, suitable for lithium batteries, can automatically adjust the charging and discharging strategy according to the battery condition;

[0019] 6. Complete electronic protection function, load overcurrent, short circuit protection, battery overcharge protection and battery low voltage protection, etc.;

[0020] 7. Using BLE 5.0Mesh technology to achieve low cost, low power consumption and high reliability. Check the real-time parameters of the controller through the mobile phone APP and modify the parameters of the controller.

[0021] 8. OTA upgrade function, the controller firmware can be upgraded OTA. After the product is sold, it will continue to be maintained by the manufacturer to ensure that the controller functions keep pace with the times, greatly reducing the time and cost of after-sales.

[0022] 9. Applied to single string (3.2V) system, integrated solar battery charge and discharge management, small size, beautiful appearance, high reliability, low failure rate and low cost.

[0023] The above description is only an overview of the technical solution of the utility model. In order to more clearly understand the technical means of the utility model, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the utility model more obvious and easy to understand, the following is a preferred embodiment, and is described in detail with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is the structure diagram of the common Bluetooth solar street light charging controller;

[0025] Figure 2 The central control Bluetooth communication module is shown;

[0026] Figure 3 A PWM charging module is shown;

[0027] Figure 4 A flat voltage and current limiting module is shown;

[0028] Figure 5A battery management module is shown;

[0029] Figure 6 A voltage sampling module is shown. DETAILED DESCRIPTION

[0030] The technical solution of the utility model will be clearly and completely described below in conjunction with specific implementation schemes, but those skilled in the art should understand that the implementation schemes described below are only used to illustrate the utility model and should not be regarded as limiting the scope of the utility model. Based on the implementation schemes in the utility model, all other implementation schemes obtained by ordinary technicians in this field without making creative work are within the scope of protection of the utility model.

[0031] The utility model adopts PHY6212 to integrate MCU and Bluetooth communication functions, which meets the cost requirements. The communication distance also meets the requirements and is not affected by sunlight. The previous handheld remote control is removed, which saves costs for both manufacturers and customers. It is replaced by a smartphone that everyone has, which is more convenient, simple and flexible. In addition, the Bluetooth communication chip can be used to achieve OTA upgrades, reducing maintenance costs.

[0032] The utility model of the common ground Bluetooth solar street light charging controller aims at the deficiencies of the prior art and provides a charging circuit of a solar charging controller with a common ground structure, which has high conversion efficiency. The battery is over-discharged for a long time due to some reasons, resulting in a voltage that is too low to provide power to the MCU. This common ground charging method can provide power to the MCU and collect the battery voltage in time when the solar panel has voltage during the day. In order to protect the battery, the controller is charged with a small current from the beginning of the design, and then charged with a large current when the battery voltage rises, which improves the service life of the solar panel and the reliability of the controller, making the solar cell voltage sampling convenient, simple in structure, and easy to implement. The discharge adopts a single power MOSFET tube constant current method, and the discharge current sampling removes the traditional op amp amplification and adopts the reference voltage resistor voltage division method. The central processor adopts PHY6212 to integrate the MCU and Bluetooth communication functions, which greatly reduces the cost.

[0033] The purpose of the utility model is to realize a charging circuit of a solar charging controller with a common ground structure through the following technical measures and reduce the controller cost by simplifying the charging and discharging circuits. It includes a solar cell, a battery, a load LED, a central processor Bluetooth communication circuit, a PWM charging circuit, a voltage leveling and current limiting circuit, a voltage sampling circuit, and a power management circuit. It also includes an anti-backflow circuit, which is connected to the PWM drive circuit, and the negative pole of the solar cell and the negative pole of the battery are connected to the common ground GND. The voltage leveling and current limiting circuit includes a power MOSFET circuit and a current sampling circuit, and the voltage sampling circuit includes a solar cell voltage sampling circuit and a battery voltage sampling circuit. Among them, the anti-backflow circuit is used to turn on the load LED for lighting at night, and the anti-backflow circuit prevents the battery voltage from flowing back to the solar cell end, causing the controller to mistakenly believe that there is electricity at the solar cell end and it is daytime, and that it is in the charging state. The controller turns off the LED drive and does not light up.

[0034] The common ground Bluetooth solar street light charging controller is specially designed for solar batteries. It provides a common ground structure solar charging controller to address the shortcomings of existing technologies. It has high conversion efficiency. The battery voltage is too low to provide MCU power due to long-term over-discharge for some reasons. This common ground charging method can provide MCU power and collect battery voltage in time when the solar panel has voltage during the day. In order to protect the battery, the controller is charged with a small current since the design. When the battery voltage rises, it is charged with a large current, which improves the service life of the solar panel and the reliability of the controller, making the solar cell voltage sampling convenient, simple in structure, and easy to implement. The controller can directly drive LED street lights, and is small in size, easy to install, and extremely convenient to use. The parameters in the controller can be read and written, and OTA upgraded through the smartphone APP. The controller uses an intelligent digital chip with integrated communication to perform load-side voltage leveling and current limiting control, which improves accuracy and reliability. The current sampling adopts the reference voltage resistor voltage division method to reduce material and maintenance costs. It supports multi-time period and LED dimming control, making load control more flexible. It also has unique short-circuit and reverse connection protection, full-function protection measures such as automatic shutdown and recovery when fully charged or over-discharged, and detailed indications of charging, battery status, load, and various faults. The chip samples parameters such as battery voltage, photovoltaic cell voltage, and discharge current, and calculates them through a dedicated control model to achieve high-precision control of discharge rate correction that meets the characteristics of the battery. It also uses an intelligent and efficient PWM charging method to charge the battery, making the most of the efficiency of the solar panel.

[0035] like Figure 1As shown in the figure, the common ground Bluetooth solar street light charging controller includes an MCU-controlled Bluetooth communication module, a PWM charging module, a power management module, a voltage leveling and current limiting module, and a voltage sampling module. It is a controller that controls solar panels, batteries, and loads. During the day, when the solar panel has voltage, a three-stage PWM charging method is used to charge the battery, and the load is turned off. At night, when the solar panel has no voltage, the load is turned on, and the battery voltage reaches the working voltage of the load through the voltage leveling module and performs current limiting output. At the same time, there is time period control to meet the user's various time period requirements.

[0036] Functions of each module:

[0037] 1. Central control Bluetooth communication module: The MCU control circuit is mainly composed of the single-chip PHY6212 chip as the main chip, which has its own 6-bit AD channel and integrated Bluetooth communication function. The system voltage sampling is realized and imported into the control algorithm for calculation, and then the control signal is output to the entire solar charge and discharge controller system. The internal integrated Bluetooth function adopts Bluetooth Mesh low-power technology, and the controller can be sent parameters and read real-time parameters through the mobile phone APP to realize OTA upgrade.

[0038] 2. PWM charging module: The negative pole of the solar cell and the negative pole of the battery are connected to the common ground GND, including the anti-backflow circuit and the PWM drive circuit. Control the solar panel to charge the battery according to the established charging curve. Avoid damage to the battery due to over-discharge, over-charge and over-voltage. Working principle: The MOS tube drive circuit and the microcontroller instruction control MOS to perform PWM charging, and the sampling circuit protects the battery from over-discharge, over-charge and over-voltage.

[0039] 3. Battery management module: provides MCU power supply, PWM drive voltage, indicator light circuit power supply to monitor and protect the battery.

[0040] 4. Voltage leveling and current limiting module: The voltage leveling and current limiting circuit includes a power MOSFET circuit and a current sampling circuit. The voltage leveling circuit is connected to the positive pole of the solar cell. The battery voltage (such as a single string of lithium iron phosphate cells is about 3.2V) is output to the load through the voltage leveling circuit (the number of load light panels is 1 string and 30 parallel light panels, and the output voltage is equal to the input voltage). The output current range is 0-10A (determined by the customer), but the power cannot exceed 30W.

[0041] 5. Voltage sampling module: collect the solar panel voltage and battery voltage through resistor voltage division. The negative pole of the solar cell and the negative pole of the battery are connected to the common ground GND, and the solar cell voltage can be collected through resistor voltage division.

[0042] Specifically, the overall circuit structure of the hardware:

[0043] 1) Central control Bluetooth communication module such as Figure 2 As shown: The main chip MCU (U1) integrates the Bluetooth communication part, and the single-chip microcomputer PHY6212 chip is used as the main chip. It has its own 6-bit AD channel to realize system voltage sampling and import it into the control algorithm for calculation and charge and discharge control. BLE 5.0Mesh technology is adopted to achieve low cost, low power consumption and high reliability. The real-time parameters of the controller can be viewed through the mobile phone APP and the parameters of the controller can be modified. The controller firmware can be upgraded OTA. After the product is sold, it will continue to be maintained by the manufacturer to ensure that the controller function keeps pace with the times, greatly reducing the time and cost of after-sales. VCC is powered by LC filtering through FB1 and C12 to supply power to the chip. C21, R24, and C20 form a π-type matching circuit, and U4 is a Bluetooth RF antenna.

[0044] 2) PWM charging module: charging control circuit such as Figure 3 As shown, the photovoltaic cell ground and the battery ground are shared. The photovoltaic cell voltage rises during the day. When the microcontroller detects that the battery voltage is lower than the set value, charging will be started. Specifically, one end of R14 (PWQG_PV) is connected to the microcontroller U1 pin. When the output is high, Q2 is turned on and grounded. Q3, Q6, Q1, and Q7 are PMOS tubes. At this time, the driving pin is turned on at a low level. When the microcontroller output is low, the PMOS tube is cut off and does not charge the battery. Among them, Q1 and Q7 are used to prevent backflow. When the photovoltaic cell has no voltage at night, the battery voltage cannot be backflowed to the photovoltaic cell end under the action of Q1 and Q7. The original diode is changed to a PMOS tube to make the charging efficiency higher.

[0045] 3) Voltage leveling and current limiting module such as Figure 4 As shown: It is suitable for single-string 3.2V battery system, and the load LED voltage is equal to the battery voltage. At night, the battery starts to discharge the load LED, and the output current is limited by the power MOS tube Q11. The opening and closing of Q11 is controlled by the single-chip microcomputer. R16 and R25 are output current sampling resistors. The collected voltage is converted into ILOAD voltage through RC filtering and connected to the AD pin of the single-chip microcomputer. The output current value is determined by the internal acquisition algorithm of the single-chip microcomputer. 1.2V is the voltage output by the MCU as the reference voltage for sampling. The sampling voltage is divided by R5 and R26 to enter the linear area of ​​the single-chip microcomputer AD, improve the resolution of AD, and finally increase the output current accuracy. And collect the discharge current to determine whether it is open circuit protection or short circuit protection. At the same time, the mobile phone APP sends the discharge current parameters to adjust the load current. The current size can be set according to various discharge mode time periods to achieve intelligent operation.

[0046] 4) Battery management module such as Figure 5As shown: In the previous solution, the photovoltaic cell ground and the battery ground are not shared. In order to meet cost requirements, power can only be taken from the battery end. There is a possibility that the battery is out of power, which makes the circuit complicated. The common ground solution takes power from the positive side of the battery and the positive side of the photovoltaic cell respectively, and connects to the input of U2 through diodes D1 and D2. The controller is always powered regardless of day or night. U2 is a low voltage difference LDO, which outputs VCC to power the microcontroller, MOS driver, and indicator light. The power supply circuit is simple and the standby power consumption is low. The common ground solution is applied to the single-string (3.2V) system, integrating the solar battery charge and discharge management, with small size and beautiful appearance, high reliability, low failure rate, and low cost.

[0047] 5) Voltage sampling module such as Figure 6 As shown in the figure: Since the photovoltaic cell ground and the battery ground are shared, the photovoltaic cell voltage collection is easier than the previous solution, and the circuit is simpler. The voltage VPV is connected to the AD pin of the microcontroller through the resistor R311 and R312 to realize the photovoltaic cell voltage collection. VBAT is the battery voltage collection. By collecting the battery voltage and the photovoltaic cell voltage, it is determined whether to discharge or charge.

[0048] The utility model adopts IP67 waterproof grade, excellent thermal balance design and natural air cooling, and can be used in various harsh environments.

[0049] Although the utility model has been described in detail above with general descriptions and specific embodiments, it is obvious to those skilled in the art that some modifications or improvements can be made to the utility model. Therefore, these modifications or improvements made without departing from the spirit of the utility model are within the scope of protection claimed by the utility model.

Claims

1. A solar charging controller with a common ground Bluetooth function, comprising a solar cell, a storage battery, a load LED, a central control MCU Bluetooth communication module, a PWM charging module, a power management module, a voltage leveling and current limiting module, a voltage sampling module, and also comprising an anti-backflow circuit, wherein the anti-backflow circuit is connected to the PWM charging module, the negative electrode of the solar cell and the negative electrode of the storage battery are connected to a common ground GND, the voltage leveling and current limiting module comprises a power MOSFET circuit and a current sampling circuit, and the voltage sampling module comprises a solar cell voltage sampling circuit and a battery voltage sampling circuit; The solar charging controller with common Bluetooth function is used to control solar panels, batteries and loads. During the day, when the solar panels have voltage, the three-stage PWM charging method is used to charge the batteries, and the load is turned off at this time; at night, when the solar panels have no voltage, the load is turned on, and the battery voltage reaches the working voltage of the load through the voltage-smoothing and current-limiting module and performs current-limiting output. At the same time, there is time period control to meet the user's various time period requirements.

2. The solar charging controller with common Bluetooth function according to claim 1, characterized in that: The solar charging controller with common Bluetooth function can directly drive LED street lights, and read and write parameters in the controller and perform OTA upgrades through a smartphone APP.

3. The solar charging controller with common Bluetooth function according to claim 1, characterized in that: The MCU Bluetooth communication module uses the single-chip PHY6212 chip as the main chip, which has its own 6-bit AD channel and integrated Bluetooth communication function. It can realize system voltage sampling and import it into the control algorithm for calculation, and then output control signals to the entire solar charge and discharge controller system. It has an internal integrated Bluetooth function and adopts Bluetooth Mesh low-power technology. It can send parameters to the controller and read real-time parameters through the mobile phone APP to realize OTA upgrade.

4. The solar charging controller with common Bluetooth function according to claim 1, characterized in that: The negative pole of the solar cell and the negative pole of the battery in the PWM charging module are connected to a common ground GND, and include a backflow prevention circuit and a PWM drive circuit, which control the solar panel to charge the battery according to a predetermined charging curve to avoid damage to the battery due to over-discharge, over-charge and over-voltage. The MOS tube is controlled to perform PWM charging through the MOS tube drive circuit and the single-chip microcomputer instruction, and the battery is protected from over-discharge, over-charge and over-voltage through the sampling circuit.

5. The solar charging controller with common Bluetooth function according to claim 1, characterized in that: The power management module provides MCU power supply, PWM drive voltage, indicator light circuit power supply, and monitors and protects the battery.

6. The solar charging controller with common Bluetooth function according to claim 1, characterized in that: The voltage-smoothing and current-limiting circuit in the voltage-smoothing and current-limiting module includes a power MOSFET circuit and a current sampling circuit. The voltage-smoothing and current-limiting circuit is connected to the positive electrode of the solar cell, and the battery voltage is output to the load through the voltage-smoothing circuit. The battery voltage of a single string of lithium iron phosphate cells is 3.2V, and the output current range is 0-10A, but the power cannot exceed 30W.

7. The solar charging controller with common Bluetooth function according to claim 1, characterized in that: The voltage sampling module collects the solar panel voltage and the battery voltage through resistor voltage division. The negative electrode of the solar cell and the negative electrode of the battery are connected to a common ground GND, and the solar cell voltage is collected through resistor voltage division.

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