A micro photovoltaic solar street light

Abstract

The invention discloses a novel micro photovoltaic solar street light, comprising a photovoltaic panel, a battery pack and an LED module, and also comprising a digital control full-bridge buck-boost circuit, a power input and output sampling circuit (5a) and a processor circuit, wherein the photovoltaic panel is electrically connected to the battery pack through the digital control full-bridge buck-boost circuit, and the power input and output sampling circuit (5a) is electrically connected to the photovoltaic panel and the processor circuit; the power input and output sampling circuit (5a) is used to sample the output voltage and current of the photovoltaic panel and then output them to the processor circuit for data collection, and the processor circuit is used to calculate the MPPT optimal power point according to the collected data and adjust the output charging voltage of the digital control full-bridge buck-boost circuit, so that the photovoltaic panel charges the battery pack at the maximum power point. The micro current is collected and boosted by the digital control full-bridge buck-boost circuit, and all of them are utilized, which can effectively improve the efficiency of converting light energy into electrical energy.

Description

Technical Field

[0001] The present application relates to the technical field of solar street lamps, and in particular to a micro photovoltaic solar street lamp. Background Art

[0002] The solar street light products currently on the market can only generate weak currents in rainy, foggy and hazy weather conditions. Traditional controllers cannot convert energy to charge the battery pack, and the micro-current generated by the solar photovoltaic panels is completely wasted and cannot be used. If there is continuous rainy weather for a long time, most manufacturers take measures to reduce the brightness of the lights to save battery energy. If there is continuous rainy weather for more than 20 days, the battery energy storage will be exhausted and stop working. When the front-end street lights stop working or fail, the back-end staff cannot know the front-end equipment status in the first time. The traditional way is to conduct manual inspections, which are delayed in maintenance and have a large workload.

[0003] Defects in the prior art:

[0004] 1) Existing solar charge controllers cannot charge the battery pack with weak current.

[0005] 2) The existing street lighting system does not have a fault detection system, remote switch, or remote brightness adjustment system. Summary of the invention

[0006] One of the purposes of the present application is to collect weak current from photovoltaic panels, track the maximum power point of the photovoltaic panels and charge the battery pack at the maximum power point.

[0007] A micro photovoltaic solar street light comprises a photovoltaic panel, a battery pack and an LED module, characterized in that it also comprises a digital control full-bridge buck-boost circuit, a power input and output sampling circuit (5a) and a processor circuit, wherein the photovoltaic panel is electrically connected to the battery pack through the digital control full-bridge buck-boost circuit, and the power input and output sampling circuit (5a) is electrically connected to the photovoltaic panel and the processor circuit; the power input and output sampling circuit (5a) is used to sample the output voltage and current of the photovoltaic panel and then output them to the processor circuit for data collection, and the processor circuit is used to calculate the MPPT optimal power point according to the collected data and adjust the output charging voltage of the digital control full-bridge buck-boost circuit, so that the photovoltaic panel charges the battery pack at the maximum power point. The micro current is collected and boosted by the digital control full-bridge buck-boost circuit, and all of it is utilized, which can effectively improve the efficiency of converting light energy into electrical energy.

[0008] As a further improvement of the technical solution of the present invention, the micro photovoltaic solar street light also includes a power input and output sampling circuit (5b) electrically connected to the battery pack, the power input and output sampling circuit (5b) is electrically connected to the battery pack and the processor circuit, the power input and output sampling circuit (5b) is used to sample the output voltage and current of the battery pack and output it to the processor circuit for data collection; the processor circuit is used to calculate the different voltage stages of the battery pack according to the collected data, and use the collected photovoltaic panel voltage and current data to enable the photovoltaic panel to charge the battery pack at different voltage stages with different currents. Specifically, the ARM chip U11 of the processor circuit reads the voltage signals CPV_VIN, CPV_BAT and the current signals CPI_VIN, CPI_BAT of the power output sampling circuit and the current amplifier circuit, and when the battery voltage is not full, the digital control full-bridge buck-boost circuit is started to charge the battery pack, and the battery is charged within the current range of different stages according to the battery voltage stage, and the output power of the photovoltaic panel is calculated at the same time, and the charging voltage is adjusted to change the charging power. Under the condition that the battery parameters are not exceeded, the maximum power point is tracked according to the MPPT charging optimization curve to charge, and the MPPT control function is realized.

[0009] As a further improvement of the technical solution of the present invention, the processor circuit is also used to obtain the current output voltage of the photovoltaic panel through the power input and output sampling circuit (5a) and generate a PWM signal to the digital control voltage regulation driver circuit, and the digital control voltage regulation driver circuit is used to convert the PWM signal into a DC voltage control signal and control the signal voltage U. The digital control voltage regulation driver circuit inputs the DC voltage control signal to the voltage feedback terminal of the digital control full-bridge buck-boost circuit to achieve adjustable output voltage of the digital control full-bridge buck-boost circuit.

[0010] As a further improvement of the technical solution of the present invention, the digitally controlled full-bridge buck-boost circuit includes a full-bridge buck-boost chip U1, the VIN lead of the digitally controlled full-bridge buck-boost circuit is connected to the output voltage of the photovoltaic panel, and the output voltage of the photovoltaic panel is adjusted by four N-channel field effect transistors Q1~Q4 controlled by the full-bridge buck-boost chip U1, and output to the battery pack through the VOUT lead for charging; wherein, the full-bridge buck-boost chip U1 has an output voltage feedback pin, the processor circuit generates a PWM signal to the DIV lead end of the digitally controlled voltage regulator controller circuit, the resistor-capacitor filter circuit in the digitally controlled voltage regulator controller circuit converts the PWM signal into a DC voltage control signal, controls the signal voltage U, and outputs the DC voltage control signal to the feedback pin of the digitally controlled full-bridge buck-boost circuit, thereby realizing the adjustable output voltage of the digitally controlled full-bridge buck-boost circuit.

[0011] The second purpose of the present application is to detect and report faults of the street lamp system, so that the staff can know the fault situation in the first time, save time and improve work efficiency. Specifically, the processor circuit is also used to detect whether the battery pack has a fault. The processor circuit counts the discharge power of the battery within a fixed voltage range through the power input and output sampling circuit (5b). When the discharge power of the battery pack is less than the nominal capacity of the battery, it is determined that the battery pack has a fault. After determining that the battery pack has a fault, the processor circuit reports the fault through the connected communication module.

[0012] As a further improvement of the technical solution of the present invention, the micro photovoltaic solar street light also includes a photosensitive sampling circuit (7a) electrically connected to the processor circuit, the photosensitive sampling circuit (7a) is used to detect the ambient light to obtain the photosensitive output voltage, and input the photosensitive output voltage into the AD converter of the processor circuit for collection; the processor circuit is used to convert the photosensitive output voltage to obtain a photosensitive value, and calculate the ambient light from the photosensitive value and calculate the reasonable output voltage range of the photovoltaic panel based on the ambient light, and compare it with the actual output voltage of the photovoltaic panel received, so as to determine whether the photovoltaic panel has a fault; after detecting that the photovoltaic panel has a fault, the fault is reported through the connected communication module. In addition, the ambient light data collected by the photosensitive is compared with the output voltage data of the photovoltaic panel, and is also used for light-controlled switch lights and automatic brightness adjustment to avoid malfunction of the light-controlled switch caused by unexpected environmental interference light.

[0013] As a further improvement of the technical solution of the present invention, the micro photovoltaic solar street light also includes an LED fault detection circuit and an LED driver circuit. The LED fault detection circuit is electrically connected to the LED driver circuit, and the LED driver circuit is used to connect and drive the LED module; the LED fault detection circuit is used to sample the working voltage of the LED module through the LED driver circuit, and input the sampling signal into the AD converter of the processor circuit for data acquisition. When the LED module is controlled to be in a working state, the processor circuit detects whether the working voltage range of the LED module is within the normal working voltage range. When the working voltage of the LED module is lower than the normal working voltage range, it is judged that a short circuit fault occurs in the LED module. When the working voltage of the LED module is equal to the battery pack voltage, it is judged that an open circuit fault occurs in the LED module.

[0014] The third purpose of the present application is to be able to remotely control the switching of LEDs and the adjustment of LED brightness. Specifically, the processor circuit also performs dimming and switching control of the light through the photosensitive value collected by the photosensitive sampling circuit (7a), wherein the processor circuit outputs a PWM signal to the LED dimming driver circuit, and the LED dimming driver circuit is used to process the PWM signal and then output a dimming drive voltage to the LED driver circuit, so as to dim the LED module connected to the LED driver circuit and perform switching control of the light.

[0015] Furthermore, the LED dimming driver circuit includes a low-power operational amplifier U13 and a resistor-capacitor filter circuit composed of a resistor R63, a resistor R64 and a capacitor C64; the processor circuit outputs a PWM signal to the LED dimming driver circuit, and the resistor-capacitor filter circuit in the LED dimming driver circuit converts the PWM signal into a DC voltage signal, and the control signal voltage U=3.3V*duty cycle, and the control signal is input to a voltage follower composed of a low-power operational amplifier U13 for processing and outputting a dimming drive voltage to the LED driver circuit, so as to dim and switch the LED module connected to the LED driver circuit.

[0016] As a further improvement of the technical solution of the present invention, it also includes a photosensitive sampling circuit (7b) electrically connected to the processor circuit, the photosensitive sampling circuit (7b) is installed at a different position from the photosensitive sampling circuit (7a), the photosensitive sampling circuit (7b) is used to detect ambient light and output a photosensitive output voltage to the processor circuit, and the processor circuit is used to correct the light value through the photosensitive sampling circuit (7b).

[0017] The present invention focuses on solving two technical bottlenecks of traditional solar street lights. 1. Traditional solar street lights can only set a minimum fixed current value to charge the battery. When the weather conditions are cloudy and rainy, the solar photovoltaic panel can only convert a very low current, and this part of the current cannot be collected and utilized by traditional products. The present invention uses a full-bridge boost circuit to collect and boost the current to achieve battery charging.

[0018] 2. When a traditional solar street light fails, the operation and maintenance personnel cannot discover it in time and can only find the fault point through on-site inspection and troubleshooting, and then carry out repairs. During the project installation, many lights need to adjust the on-site illumination due to different environmental illumination. Traditional solar street lights can only be adjusted on-site through a remote control. If changes are needed later, it is still necessary to use the remote control for on-site adjustment, which is very inconvenient. The present invention adopts a fault detection module and a communication module to realize automatic detection of lamp body faults and send them to the back-end unified management platform through the communication module, so that the back-end operation and maintenance can obtain fault information in the first time and identify the faulty components at the same time. During the construction process, the remote communication module can also realize the centralized management of the solar street light platform in the entire area and remotely adjust the parameters.

[0019] A micro photovoltaic solar street light comprises an LED module, a photovoltaic panel, a battery pack, a communication module and an intelligent control system, a plurality of optional communication modules, an LED module with adjustable brightness and an intelligent control system capable of realizing a plurality of functions, wherein the functions of the intelligent control system include but are not limited to: tracking the maximum power point (MPPT) of the photovoltaic panel, multi-stage charging control according to the battery status, battery overcharge and over-discharge protection, automatic adjustment of LED brightness according to the battery power, remote setting of working parameters and a plurality of working modes, detection of equipment failure and automatic uploading, and the intelligent control system comprises a fault detection circuit, a 3.3V power supply circuit, a dimming control circuit, an MPPT control circuit and an ARM processor circuit.

[0020] After the voltage of the photovoltaic panel is adjusted by the digital full-bridge buck-boost circuit, the battery pack is charged; the power input and output sampling circuit (included in the fault detection circuit) samples the output voltage and current of the photovoltaic panel, and inputs them into the ARM AD converter for data acquisition. The ARM calculates the MPPT optimal power point and adjusts the output charging voltage of the digital full-bridge buck-boost circuit, thereby adjusting the charging power and charging the battery pack at the maximum power point.

[0021] Preferably, the micro photovoltaic solar street light further includes a photosensitive circuit, a fault detection circuit, an ARM control circuit and a communication bus interface circuit. After detecting a fault, the ARM chip U11 sends fault information to the communication bus interface P1 through pins 33 to 39, and realizes fault reporting through the communication module of the communication bus interface.

[0022] Preferably, the method by which the processor circuit determines whether the photovoltaic panel is faulty is as follows: a photosensitivity sampling circuit detects the photosensitivity output voltage, a power input sampling circuit (included in a fault detection circuit) detects the photovoltaic panel output voltage, and the data is input to the AD converter of the ARM for data acquisition. The ARM calculates the ambient light through the photosensitivity value, and obtains a reasonable output voltage range for the photovoltaic panel, and compares the actual output voltage of the photovoltaic panel to determine whether the photovoltaic panel is faulty.

[0023] Preferably, the processor circuit also detects whether the battery pack has a fault, and the method is: the battery voltage and current are sampled by the power input and output sampling circuit of the battery pack output voltage and current (contained in the fault detection circuit), and the data is input to the AD converter of the ARM for data acquisition. The ARM counts the discharge power of the battery within a fixed voltage range. When the battery discharge power is much less than the nominal capacity of the battery, it is determined that the battery has a fault.

[0024] Preferably, the processor circuit also detects whether the LED module fails, and the method is: the LED driver output voltage sampling circuit (i.e., LED fault detection circuit) (included in the fault detection circuit) samples the working voltage of the LED lamp bead, and inputs it into the AD converter of the ARM for data acquisition, and detects whether the working voltage range of the LED lamp bead is within the normal working voltage range when the control state is the light-on state (the working voltage range of a fixed number of LED lamp beads is relatively constant). When the LED driver is in the step-down constant current working mode, according to the working characteristics of the step-down constant current circuit, if the working voltage of the LED lamp bead is lower than the normal voltage range, it is judged that the LED has a short circuit fault, and if the working voltage of the LED lamp bead is equal to the battery pack voltage, it is judged that the LED has an open circuit fault.

[0025] Preferably, in the digitally controlled full-bridge buck-boost circuit, (1) the full-bridge circuit is a 4-transistor circuit, (2) the voltage feedback of the buck-boost circuit is processed by proportional amplification by an operational amplifier, and (2) the proportional amplification factor of the operational amplifier is controlled by an ARM input DC voltage signal.

[0026] The circuit consists of a dedicated full-bridge buck-boost chip U1: LTC3780, 4 N-channel field effect transistors Q1~Q4, power inductors L1~L2, and digital control voltage regulator driver U4. The output voltage of the photovoltaic panel is input by the VIN lead in the digital control full-bridge buck-boost circuit diagram, and the voltage is adjusted by the 4-tube full-bridge buck-boost circuit controlled by LTC3780, and then output to the battery through the VOUT lead for charging. Among them, pin 6 of LTC3780 is the output voltage feedback pin. The voltage-controlled proportional amplifier composed of U4 proportionally adjusts the output terminal VOUT voltage and inputs it to the LTC3780 voltage feedback pin 6, so that the output voltage can be adjusted between 8V and 16V to meet the charging voltage requirement of the 11.1V lithium battery pack; the DIV lead of the CNC voltage regulator driver is the voltage regulation terminal, and the PWM signal is generated by pin 56 of the ARM chip U11, which is converted into a DC voltage control signal through the resistor-capacitor filter circuit composed of R33, R35, and C28. The control signal voltage U=3.3V*duty cycle.

[0027] Preferably, the input and output current sampling circuits of the digital full-bridge buck-boost circuit are high-end current sampling, and are composed of U2 and U3 current sampling dedicated chips INA213. Preferably, the MPPT control circuit includes a digital full-bridge buck-boost circuit, a digital voltage regulation driver circuit, a power supply output sampling circuit, a current amplifier circuit, and a processor module. The ARM chip U11 reads the voltage signals CPV_VIN, CPV_BAT and the current signals CPI_VIN, CPI_BAT of the power supply output sampling circuit and the current amplifier circuit through ADC pins 24 to 27. When the battery voltage is not full, the digital full-bridge buck-boost circuit is started to charge the battery pack, and the battery is charged within the current range of different stages according to the battery voltage stage. At the same time, the output power of the photovoltaic panel is calculated, and the charging voltage is adjusted to change the charging power. Without exceeding the battery parameters, the maximum power point is tracked for charging according to the MPPT charging optimization curve to realize the MPPT control function.

[0028] Preferably, the processor circuit includes an ARM chip U11 of model STM32F103. Among them, pins 33 to 39 of U11 are used as signal bus interfaces, and an external communication expansion module is used for fault uploading and remote control; pins 14 and 15 of U11 are photosensitive circuit AD sampling interfaces, which are used to read the photosensitive value to detect the ambient light illumination, and to control the lighting on and off of the LED lamp; pins 20 to 23 of U11 are LED driver output voltage AD sampling interfaces, which are used to read the lamp bead voltage output by the LED fault detection circuit and detect LED faults; pins 24 to 27 of U11 are voltage and current AD sampling interfaces of photovoltaic panels and battery packs, which are used to read the signals of the power input and output sampling circuit CPV_VIN and CPV_BAT and the CPI_VIN and CPI_BAT signals of the current amplifier circuit, and are used to control the MPPT charging function and photovoltaic panel and battery pack fault detection.

[0029] Preferably, the 3.3V regulated power supply circuit is a 3.3V precision regulated power supply circuit composed of U6: AMS1117-3.3 and U7: XL1509-5.0. The photovoltaic panel and the battery pack power U7 through D9 and D11. After being stepped down to 5V by U7, it is input to U6 for precision stabilization to 3.3V, which is used to power the components of the 3.3V power supply circuit.

[0030] Preferably, in the micro photovoltaic solar street light, the LED module uses multiple groups of LED driver circuits with adjustable brightness and detectable faults, the LED driver constant current chip is PT4115, and the voltage signal is input through the chip pin 3 to control the switch light and dimming, and the light is turned off when the voltage is lower than 0.3V; the PWM signal is generated by the 43rd pin of the ARM chip U11, and converted into a DC voltage control signal through the resistor-capacitor filter circuit composed of R63, R64, and C46, ​​and the control signal voltage U=3.3V*duty cycle, and the control signal is input to the voltage follower composed of the single op amp U13 to output the dimming drive voltage to the ADJ lead, and the LED driver circuit is dimmed and the switch light is controlled. The fault detection circuit is a high-end voltage sampling circuit composed of an op amp subtractor, and the voltage at both ends of the lamp bead is obtained through the subtractor, and the fault is detected according to the voltage range.

[0031] Preferably, the LED module is a low-power array LED light-emitting body or a COB LED light-emitting body.

[0032] "The micro photovoltaic solar street light proposed in this application is to solve the problem of converting light energy into electrical energy and storing it in a battery pack under weak light conditions in rainy weather. The present invention adds the following modules to the existing warning lights: intelligent control system, photovoltaic panel module, and battery pack module. The system structure is as follows: Figure 1 :1: Photovoltaic panel: ※ Responsible for converting light energy into electrical energy. 2: Intelligent control system: ※ Realize the buck-boost function, and realize automatic tracking of the maximum power point to charge the battery pack. ※ Realize the network interface function, the network can be optical path / wireless 4G / 5G / RS485 / Internet of Things protocol LoRa / NB-IoT, etc. Responsible for remote communication. ※ Realize fault detection, such as LED module not emitting light, battery pack failure, etc. ※ Realize functions such as automatic light switch / remote light switch / remote brightness adjustment / brightness self-adjustment. 3: LED module: ※ Use low-power array or COB LED light sources to achieve lighting. The key points of the present invention: 1) The weak current generated under dim light charges the battery. 2) When charging the battery, the maximum power point tracking technology is used. 3) Equipment failure can realize remote alarm. Compared with the prior art, the advantages of this application are:

[0033] 1) The micro photovoltaic solar street light of the present application can track the maximum power point of the photovoltaic panel, so that the battery pack can be charged at the maximum power point; it can effectively improve the efficiency of converting light energy into electrical energy.

[0034] 2) The present application can detect in real time whether there is a fault in the photovoltaic panel, battery pack and LED module, and report the fault through the communication module after the fault is detected; so that the staff can know the specific fault information in the first time, thereby improving the maintenance efficiency.

[0035] 3) This application can control the dimming and switching of LED modules.

[0036] 4) It can be easily installed and can realize fast operation and maintenance management after networking, thus saving costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a principle block diagram of the micro photovoltaic solar street light of the embodiment of the present application;

[0038] Figure 2 is a circuit schematic diagram of a processor circuit according to an embodiment of the present application;

[0039] Figure 3 is a circuit schematic diagram of a digitally controlled full-bridge buck-boost circuit according to an embodiment of the present application (a is an overall circuit schematic diagram; Figure 3 The circuit diagram is relatively large. Figure 3 Clearly visible, Figure 3 Divided into two parts, a1 is the circuit schematic diagram after the left half of a is enlarged, and a2 is the circuit schematic diagram after the right half of a is enlarged);

[0040] Figure 4 is a circuit schematic diagram of a digitally controlled voltage regulating driver circuit according to an embodiment of the present application;

[0041] Figure 5 It is a circuit schematic diagram of the power input and output sampling circuit of the embodiment of the present application (wherein the power input and output sampling circuit 5a is used to detect the output voltage and current of the photovoltaic panel, and the power input and output sampling circuit 5b is used to detect the output voltage and current of the battery pack);

[0042] Figure 6 : is a circuit schematic diagram of a current sampling amplifier circuit of an embodiment of the present application (wherein the current sampling amplifier circuit 6a is used to amplify the output current of the power input and output sampling circuit 5a, and the current sampling amplifier circuit 6b is used to amplify the output current of the power input and output sampling circuit 5b);

[0043] Figure 7 is a circuit schematic diagram of a photosensitive sampling circuit according to an embodiment of the present application;

[0044] Figure 8 is a circuit schematic diagram of an LED dimming driver circuit according to an embodiment of the present application;

[0045] Fig. 9 is a circuit schematic diagram of an LED driver circuit according to an embodiment of the present application;

[0046] Fig.10 is a circuit schematic diagram of an LED fault detection circuit according to an embodiment of the present application;

[0047] Fig.11 is a circuit schematic diagram of a communication bus interface of an embodiment of the present application;

[0048] Fig.12 is a circuit schematic diagram of a 3.3V voltage-stabilized power supply circuit according to an embodiment of the present application;

[0049] Fig.13 is a circuit schematic diagram of a programming interface according to an embodiment of the present application;

[0050] Fig.14 This is a positioning mark diagram of the placement machine in an embodiment of the present application. DETAILED DESCRIPTION

[0051] The technical solution of the present invention is further described in detail below with reference to the accompanying drawings.

[0052] like Figure 1 As shown, a micro photovoltaic solar street light includes a photovoltaic panel 1, a battery pack 15, an LED module 16 and an intelligent control system, wherein the intelligent control system includes a digital control full-bridge buck-boost circuit 3, a fault detection circuit and a processor circuit 2, wherein the photovoltaic panel 1 is electrically connected to the battery pack 15 through the digital control full-bridge buck-boost circuit 3, and the battery pack is electrically connected to the LED module to supply power to the LED module. The fault detection circuit is electrically connected to the photovoltaic panel to detect whether there is a fault in the photovoltaic panel, and the fault detection circuit is also electrically connected to the digital control full-bridge buck-boost circuit 3 and the processor circuit 2, and the processor circuit 2 is electrically connected to the battery pack, the LED module and the digital control full-bridge buck-boost circuit 3.

[0053] The fault detection circuit includes a power input and output sampling circuit 5, which samples the output voltage and current of the photovoltaic panel and outputs them to the processor circuit 2 for data collection. The processor circuit 2 calculates the MPPT optimal power point based on the collected data and adjusts the output charging voltage of the digital full-bridge buck-boost circuit 3, so that the photovoltaic panel charges the battery pack at the maximum power point. Figure 5 As shown, the power input and output sampling circuit 5 is provided with two, namely, the power input and output sampling circuit 5a for sampling the photovoltaic panel voltage and the power input and output sampling circuit 5b for sampling the battery pack voltage. Figure 5 As shown in (a), the power input and output sampling circuit 5a includes a capacitor C15, a resistor R13, a resistor R15 and a photovoltaic panel interface P2. The photovoltaic panel interface P2 is used to connect the photovoltaic panel. Pin 1 of the photovoltaic panel interface P2 is respectively connected to one end of the capacitor C15 and one end of the resistor R13 through a GND lead. Pin 2 of the photovoltaic panel interface P2 is connected to one end of the resistor R14 and a CPI_VIN+ lead. The other end of the resistor R14 is connected to one end of the VIN lead and a CPI_VIN- lead. The other end of the VIN lead is connected to one end of the resistor R15. The other end of the capacitor C15 is connected to the other end of the resistor R13, the other end of the resistor R15 and a CPV_VIN lead.

[0054] The power input and output sampling circuit 5a is used to sample the output voltage and current of the photovoltaic panel and amplify the output current of the photovoltaic panel through the current sampling amplifier circuit 6 for output. Specifically, Figure 6 As shown in (a), the current sampling amplifier circuit 6a includes a current monitor U2 of model INA213AIDCKR, and the pins 5 and 4 of the current monitor U2 are respectively connected to the CPI_VIN- lead and CPI_VIN+ lead of the power input and output sampling circuit 5a, and the photovoltaic panel output current signal collected by the power input and output sampling circuit 5a is amplified and output through the CPI_VIN lead connected to the pin 6 of the current monitor U2. The power input and output sampling circuit 5a and the current sampling amplifier circuit 6a sample the output voltage and current of the photovoltaic panel and output them to the processor circuit. Figure 5 As shown in (a) and 6(a), the power input and output sampling circuit 5a inputs the detected photovoltaic panel output voltage and current signals through the CPV_VIN lead and the current sampling amplifier circuit 6a inputs the detected photovoltaic panel output voltage and current signals through the CPI_VIN lead into the AD converter of the processor circuit 2 for data acquisition.

[0055] Specifically, Figure 2 The processor circuit 2 includes an ARM chip U11 of model STM32F103RCT6, the 24th pin of the ARM chip U11 is a photovoltaic panel output voltage signal sampling interface, the 25th pin of the ARM chip U11 is a photovoltaic panel output current signal sampling interface, and the 24th pin and the 25th pin of the ARM chip U11 are respectively connected to the CPV_VIN pin of the power input and output sampling circuit 5a and the CPI_VIN pin of the current sampling amplifier circuit 6a through the ADC_INI4 and ADC_INI5 pins. The processor circuit 2 calculates the MPPT optimal power point of the collected data, and adjusts the output charging voltage of the digital full-bridge buck-boost circuit 3, so that the photovoltaic panel 1 charges the battery pack 15 at the maximum power point.

[0056] Among them, Figure 3As shown, the digital control full-bridge buck-boost circuit 3 includes a full-bridge buck-boost chip U1 of model LTC3780IG, four N-channel field effect transistors Q1-Q4, and power inductors L1-L2. The output voltage of the photovoltaic panel 1 is input through the VIN lead of the digital control full-bridge buck-boost circuit 3, and the voltage is adjusted by the four N-channel field effect transistors Q1-Q4 controlled by the full-bridge buck-boost chip U1, and then output to the battery through the VOUT lead for charging. Among them, pin 6 of the full-bridge buck-boost chip U1 is the output voltage feedback pin. The voltage-controlled proportional amplifier composed of the input / output operational amplifier U4 adjusts the output voltage VOUT proportionally, and then inputs it into the feedback pin 6 of the full-bridge buck-boost chip U1, so that the output voltage of the digital control full-bridge buck-boost circuit can be adjusted between 8V and 16V, meeting the charging voltage requirement of the 11.1V lithium battery pack. Specifically, the digital control full-bridge buck-boost circuit 3 is driven by the digital control voltage regulator driver circuit 4 to adjust the output voltage of the photovoltaic panel, and the digital control voltage regulator driver circuit is controlled and driven by the processor circuit. The processor circuit 2 will first obtain the current output voltage of the photovoltaic panel according to the power input and output sampling circuit, and then control the digital control full-bridge buck-boost circuit to output the required voltage by adjusting the digital control voltage regulator driver circuit. Figure 2 As shown, the pin 56 of the ARM chip U11 of the processor circuit generates a PWM signal and outputs the PWM signal to the DIV lead end of the digital control voltage regulator driver circuit 4 through the DIV lead connected to the pin 56. The resistor-capacitor filter circuit composed of resistors R33, R35 and capacitor C28 in the digital control voltage regulator driver circuit 4 converts the PWM signal into a DC voltage control signal, and the control signal voltage U=3.3V*duty cycle. The DC voltage control signal of the digital control voltage regulator driver circuit 4 is input into the voltage feedback pin 6 of the full-bridge buck-boost chip U1 of the digital control full-bridge buck-boost circuit 3 through the VoSense lead, so as to achieve the output voltage adjustable between 8V and 16V. (Wherein, the VOUT lead of the digital control voltage regulator driver circuit 4 and the VOUT line of the digital control full-bridge buck-boost circuit 3 are the same lead.) The digital control full-bridge buck-boost circuit is connected to the battery pack through its VOUT lead to charge the battery pack.

[0057] Furthermore, the processor circuit 2 is also used to determine whether the photovoltaic panel is faulty. Specifically, the micro photovoltaic solar street light also includes a photosensitive sampling circuit 7 and a communication module, such as Figure 7The photosensitive sampling circuit 7 is provided with two, namely, the photosensitive sampling circuit 7a and the photosensitive sampling circuit 7b. The photosensitive sampling circuit 7a includes a photoresistor GR1, and the photosensitive sampling circuit 7a detects the ambient light through the photoresistor GR1 to obtain the photosensitive output voltage and inputs the photosensitive output voltage to the ADC_IN0 lead connected to the pin 14 of the ARM chip U11 of the processor circuit 2 through the ADC_IN0 lead; the ARM chip U11 performs digital-to-analog conversion on the received photosensitive output voltage to obtain a photosensitive value, and the ARM chip U11 calculates the ambient light through the photosensitive value to obtain a reasonable output voltage range of the photovoltaic panel, and compares it with the actual output voltage of the photovoltaic panel received, so as to determine whether the photovoltaic panel is faulty. When the processor circuit detects that the photovoltaic panel is faulty, the communication bus interface 11 connected to the 33-39 pins of the ARM chip U11 is connected to the communication module to report the fault.

[0058] Furthermore, the photosensitive value collected by the processor circuit 2 through the photosensitive sampling circuit (7a) is used not only for comparison with the output voltage data of the photovoltaic panel to detect whether the photovoltaic panel is faulty, but also for dimming and switching the LED module. Specifically, the LED module uses a plurality of sets of LED driver circuits 9a-9d with adjustable brightness and detectable faults. The LED driver circuits 9a, 9b, 9c, and 9d respectively include LED driver constant current chips U5, U8, U10, and U12 of model PT4115. The LED driver constant current chips U5, U8, U10, and U12 are respectively connected to the LED dimming driver circuit 8 through the ADJ lead connected to pin 3. The pin 3 of the low-power operational amplifier U13 of the LED dimming driver circuit 8 is connected to the pin 43 of the ARM chip U11 of the processor circuit 2 through the DIM lead. Pin 43 of the ARM chip U11 outputs a PWM signal to the LED dimming driver circuit 8, which is converted into a DC voltage signal by the RC filter circuit (composed of a resistor R63, a resistor R64 and a capacitor C46) in the LED dimming driver circuit, and the control signal voltage U=3.3V*duty cycle. The control signal is input into a voltage follower composed of a low-power operational amplifier U13 for processing and outputting a dimming drive voltage. The dimming drive voltage is transmitted to the LED driver circuit through the ADJ lead connected to pin 1 of the low-power operational amplifier U13, and the LED module connected to the LED driver circuit is dimmed and the switch light is controlled; wherein the processor circuit is also set at different brightnesses of the LED module according to the relationship curve between the battery voltage and capacity.

[0059] Furthermore, the micro photovoltaic solar street light also includes a photosensitive sampling circuit (7b), which is connected to the pin 15 of the ARM chip U11 of the processor circuit through ADC_IN1. The installation position of the photosensitive sampling circuit (7b) is different from the installation position of the photosensitive sampling circuit (7a), and is used for light value correction. The processor circuit tracks the photosensitive values ​​collected by the two photosensitive sampling circuits. When the two values ​​are close, they are considered normal. If the two values ​​differ greatly, it is due to environmental influences, such as the influence of car light illumination. When the difference between the two values ​​is large, the processor circuit continues to track the two photosensitive values. Only when the two values ​​are close, the processor circuit starts to perform the above-mentioned judgment on whether the photovoltaic panel is faulty, or whether the LED module needs to be dimmed or switched on and off.

[0060] Furthermore, the processor circuit 2 can also be used to detect whether a battery pack has a fault. The output voltage and current of the battery pack are sampled through the power input and output sampling circuit 5b, and the current sample is amplified by the current sampling amplifier 6b and input into the AD converter of the processor circuit 2 for data acquisition. The processor circuit 2 counts the discharge power of the battery pack 15 within a fixed voltage range. When the discharge power of the battery pack is less than the nominal capacity of the battery, it is determined that the battery pack has a fault, and the fault is reported through the communication bus interface and the communication module electrically connected to the processor. Specifically, the output voltage end of the battery pack is connected to the battery interface P3 of the power input and output sampling circuit 5b, pin 1 of the battery interface P3 is connected to one end of the capacitor C23 and one end of the resistor R17 through the GND lead, pin 2 of the battery interface P3 is connected to the CPI_BAT+ lead and one end of the resistor R18, the other end of the resistor R18 is connected to the CPI_BAT- lead and one end of the VOUT lead, the other end of the VOUT lead is connected to the CPV_BAT lead through the resistor R19, and the other end of the capacitor C23 is connected to the other end of the resistor R17 and the CPV_BAT lead. The current sampling amplifier 6b includes a current monitor U3 of model INA213AIDCKR, pins 5 and 4 of the current monitor U3 are respectively connected to the CPI_BAT- lead and CPI_BAT+ lead of the power input and output sampling circuit 5b, pin 6 of the current monitor U3 is connected to the CPI BAT lead, and the CPI BAT lead and CPV_BAT lead are respectively connected to pins 27 and 26 of the ARM chip U11 of the processor circuit 2, and the processor circuit 2 counts the discharge power within the fixed voltage range of the battery, and if the discharge power of the battery pack is less than the nominal capacity of the battery, it is determined that the battery pack is faulty. When the battery pack fails, the ARM chip U11 reports the fault through the communication bus interface 11 connected to pins 33 to 39 (the interface P1 of the communication bus interface 11 is connected to the communication module).

[0061] Furthermore, the processor circuit can also use different currents for charging according to different voltage stages of the battery. Specifically, the ARM chip U11 of the processor circuit 2 reads the voltage signals CPV_VIN and CPV_BAT and the current signals CPI_VIN and CPI BAT of the power input and output sampling circuit and the current sampling amplifier circuit through the pins. When the battery pack voltage is not full, the digital full-bridge buck-boost circuit is started to charge the battery pack, and the battery is charged within the current range of different stages according to the battery voltage stage (the voltage and current are sampled through the power input and output sampling circuit, where the current is amplified by the "current sampling amplifier circuit" and then input into the "processor circuit" to sample the current current. Finally, different currents are used for charging according to the different voltage stages of the battery.), and at the same time, the output power of the photovoltaic panel is calculated, the charging voltage is adjusted to change the charging power, and the maximum power point is tracked for charging according to the MPPT charging optimization curve without exceeding the battery parameters to realize the MPPT control function.

[0062] Furthermore, the processor circuit 2 can also be used to monitor whether the LED module fails. Fig.10 The four groups of LED fault detection in the circuit) include a single-power four-way operational amplifier U9 of model LN324DR, wherein pins 2 and 3 of the single-power four-way operational amplifier U9 are connected to the LED driver circuit 9a (i.e., Fig. 9In the embodiment, the LED driver circuit 9 is provided with four LED driver circuits, namely, LED driver circuits 9a, 9b, 9c, and 9d. Pins 5, 6, pins 10, 9, and pins 13, 12 of the single-power four-way operational amplifier U9 of the LED fault detection circuit 10 are respectively connected to the LED driver circuit 9b, LED driver circuit 9c, and LED driver circuit 9d through the LED H2 and LED L2 leads, LED H3 and LED L3 leads, and LED L4 and LED H4 leads; the number of LED driver circuits can also be adjusted according to user needs. The LED fault detection circuit 10 samples the working voltage of the LED module through the LED driver circuit 9a (9b, 9c, 9d), and inputs it into the AD converter of the ARM chip U11 for data acquisition. Specifically, the pin 1, pin 7, pin 8, and pin 14 of the LED fault detection circuit 10 are respectively connected to the pins 20-23 of the ARM chip U11 of the processor circuit 2 through the CP_LED1 lead, the CP_LED2 lead, the CP_LED3 lead, and the CP_LED4 lead. When the LED module is controlled to be in the light-on state, the ARM chip U11 detects whether the working voltage range of the LED module is within the normal working voltage range (the working voltage range of a fixed number of LED lamp beads is relatively constant). When the LED driver circuit 9a (9b, 9c, 9d) is in the step-down constant current working mode, according to the working characteristics of the step-down constant current circuit, if the ARM chip U11 detects that the working voltage of the LED lamp beads is lower than the normal voltage range, it is determined that the LED module has a short circuit fault. If the LED lamp bead voltage is equal to the battery pack voltage, it is determined that the LED module has an open circuit fault. After detecting that a fault occurs in the LED module, the ARM chip U11 reports the fault through the communication bus interface and the communication module.

[0063] In this embodiment, the 3.3V voltage-stabilized power supply circuit 12 is composed of a 3.3V precision voltage-stabilized power supply circuit composed of a forward low-voltage dropout voltage regulator U6 of model AMS1117-3.3 and a buck chip U7 of model XL1509-5.0. The buck chip U7 is powered by the photovoltaic panel and the battery pack through diodes D9 and D11 respectively. After the buck chip U7 steps down the voltage to 5V, it is input to the forward low-voltage dropout voltage regulator U6 for precision voltage stabilization to 3.3V, which is used to power the components of the 3.3V power supply circuit. Further, in the embodiment of the present application, the LED module adopts a low-power array LED light source or a COB LED light source.

Claims

1. A micro photovoltaic solar street light, comprising a photovoltaic panel, a battery pack and an LED module, characterized in that: It also includes a digitally controlled full-bridge buck-boost circuit, a power input and output sampling circuit (5a) and a processor circuit. The photovoltaic panel is electrically connected to the battery pack via the digitally controlled full-bridge buck-boost circuit. The power input and output sampling circuit (5a) is electrically connected to the photovoltaic panel and the processor circuit. The power input and output sampling circuit (5a) is used to sample the output voltage and current of the photovoltaic panel and then output them to the processor circuit for data collection. The processor circuit is used to calculate the MPPT optimal power point based on the collected data and adjust the output charging voltage of the digitally controlled full-bridge buck-boost circuit so that the photovoltaic panel charges the battery pack at the maximum power point. The processor circuit is also used to detect whether the battery pack has a fault. The processor circuit counts the discharge power of the battery within a fixed voltage range through a power input and output sampling circuit (5b). When the discharge power of the battery pack is less than the nominal capacity of the battery, it is determined that the battery pack has a fault. After determining that the battery pack has a fault, the processor circuit reports the fault through a connected communication module. The processor circuit is also used to perform dimming and light switching control based on the photosensitive value collected by the photosensitive sampling circuit (7a), wherein the processor circuit outputs a PWM signal to the LED dimming driver circuit, and the LED dimming driver circuit is used to process the PWM signal and then output a dimming drive voltage to the LED driver circuit, so as to perform dimming and light switching control on the LED module connected to the LED driver circuit; The digital control full-bridge buck-boost circuit includes a full-bridge buck-boost chip U1 of model LTC3780IG, four N-channel field effect transistors Q1-Q4, power inductors L1-L2 and a digital control voltage regulator driver U4; the output voltage of the photovoltaic panel is input by the VIN lead of the digital control full-bridge buck-boost circuit, and the voltage is adjusted by the 4-tube full-bridge buck-boost circuit controlled by the full-bridge buck-boost chip U1, and then output by the VOUT lead to the battery for charging; the 6th pin of the full-bridge buck-boost chip U1 is the output voltage feedback pin, and the voltage-controlled proportional amplifier composed of the input / output operational amplifier U4 proportionally adjusts the output VOUT voltage, and then inputs it into the voltage feedback pin 6 of the full-bridge buck-boost chip U1, so as to realize the output of the digital control full-bridge buck-boost circuit. The voltage is adjustable between 8V and 16V, meeting the charging voltage requirement for an 11.1V lithium battery pack; wherein, pin 56 of the ARM chip U11 of the processor circuit generates a PWM signal and outputs the PWM signal to the DIV lead end of the digital control voltage regulator driver circuit 4 through the DIV lead connected to pin 56, and the resistor-capacitor filter circuit composed of resistors R33, R35 and capacitor C28 in the digital control voltage regulator driver circuit 4 converts the PWM signal into a DC voltage control signal, and the control signal voltage U=3.3V*duty cycle, and the DC voltage control signal of the digital control voltage regulator driver circuit 4 is input into the voltage feedback pin 6 of the full-bridge buck-boost chip U1 of the digital control full-bridge buck-boost circuit 3 through the VoSense lead, so as to achieve an adjustable output voltage between 8V and 16V; The power input and output sampling circuit (5a) comprises a capacitor C15, a resistor R13, a resistor R15 and a photovoltaic panel interface P2. The photovoltaic panel interface P2 is used to connect the photovoltaic panel. Pin 1 of the photovoltaic panel interface P2 is respectively connected to one end of the capacitor C15 and one end of the resistor R13 through a GND lead. Pin 2 of the photovoltaic panel interface P2 is connected to one end of the resistor R14 and a CPI_VIN+ lead. The other end of the resistor R14 is connected to one end of a VIN lead and a CPI_VIN- lead. The other end of the VIN lead is connected to one end of the resistor R15. The other end of the capacitor C15 is connected to the other end of the resistor R13, the other end of the resistor R15 and a CPV_VIN lead.

2. A micro photovoltaic solar street light according to claim 1, characterized in that: It also includes a power input and output sampling circuit (5b) electrically connected to the battery pack, and the power input and output sampling circuit (5b) is used to sample the output voltage and current of the battery pack and output them to the processor circuit for data collection; The processor circuit is used to calculate different voltage stages of the battery pack according to the collected data, and to enable the photovoltaic panel to charge the battery packs of different voltage stages with different currents through the collected photovoltaic panel voltage and current data.

3. A micro photovoltaic solar street light according to claim 1 or 2, characterized in that: The processor circuit is also used to obtain the current output voltage of the photovoltaic panel through the power input and output sampling circuit (5a) and generate a PWM signal to the digital control voltage regulation driver circuit. The digital control voltage regulation driver circuit is used to convert the PWM signal into a DC voltage control signal and control the signal voltage U. The digital control voltage regulation driver circuit inputs the DC voltage control signal to the voltage feedback terminal of the digital control full-bridge buck-boost circuit to achieve adjustable output voltage of the digital control full-bridge buck-boost circuit.

4. A micro photovoltaic solar street light according to claim 3, characterized in that: The digital control full-bridge buck-boost circuit includes a full-bridge buck-boost chip U1, the VIN lead of the digital control full-bridge buck-boost circuit is connected to the output voltage of the photovoltaic panel, and the output voltage of the photovoltaic panel is adjusted by four N-channel field effect transistors Q1~Q4 controlled by the full-bridge buck-boost chip U1, and output to the battery pack through the VOUT lead for charging; wherein, the full-bridge buck-boost chip U1 has an output voltage feedback pin, the processor circuit generates a PWM signal to the DIV lead end of the digital control voltage regulator controller circuit, the resistor-capacitor filter circuit in the digital control voltage regulator controller circuit converts the PWM signal into a DC voltage control signal, controls the signal voltage U, and outputs the DC voltage control signal to the feedback pin of the digital control full-bridge buck-boost circuit, so as to realize the adjustable output voltage of the digital control full-bridge buck-boost circuit.

5. A micro photovoltaic solar street light according to claim 1 or 2, characterized in that: It also includes a photosensitive sampling circuit (7a) electrically connected to the processor circuit, the photosensitive sampling circuit (7a) is used to detect the ambient light to obtain a photosensitive output voltage, and input the photosensitive output voltage into an AD converter of the processor circuit for collection; the processor circuit is used to convert the photosensitive output voltage to obtain a photosensitive value, and calculate the ambient light from the photosensitive value, and calculate a reasonable output voltage range of the photovoltaic panel based on the ambient light, and compare it with the received actual output voltage of the photovoltaic panel, so as to determine whether the photovoltaic panel has a fault; After a photovoltaic panel fault is detected, the fault is reported through the connected communication module.

6. A micro photovoltaic solar street light according to claim 1 or 2, characterized in that: The micro photovoltaic solar street light also includes an LED fault detection circuit and an LED driver circuit. The LED fault detection circuit is electrically connected to the LED driver circuit, and the LED driver circuit is used to connect and drive the LED module; the LED fault detection circuit is used to sample the working voltage of the LED module through the LED driver circuit, and input the sampling signal into the AD converter of the processor circuit for data acquisition. When the LED module is controlled to be in a working state, the processor circuit detects whether the working voltage range of the LED module is within the normal working voltage range. When the working voltage of the LED module is lower than the normal working voltage range, it is judged that a short circuit fault occurs in the LED module. When the working voltage of the LED module's lamp beads is equal to the battery pack voltage, it is judged that an open circuit fault occurs in the LED module.

7. The micro photovoltaic solar street light according to claim 1, characterized in that: The LED dimming driver circuit includes a low-power operational amplifier U13 and a resistor-capacitor filter circuit composed of a resistor R63, a resistor R64 and a capacitor C64; the processor circuit outputs a PWM signal to the LED dimming driver circuit, and the resistor-capacitor filter circuit in the LED dimming driver circuit converts the PWM signal into a DC voltage signal, and the control signal voltage U=3.3V*duty cycle, and the control signal is input to a voltage follower composed of a low-power operational amplifier U13 for processing and outputting a dimming drive voltage to the LED driver circuit, so as to dim the LED module connected to the LED driver circuit and control the switching of the light.

8. The micro photovoltaic solar street light according to claim 1, characterized in that: It also includes a photosensitive sampling circuit (7b) electrically connected to the processor circuit, the photosensitive sampling circuit (7b) and the photosensitive sampling circuit (7a) are installed at different positions, the photosensitive sampling circuit (7b) is used to detect ambient light and output a photosensitive output voltage to the processor circuit, and the processor circuit is used to correct the light value through the photosensitive sampling circuit (7b).

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