Photovoltaic control system

Abstract

The invention relates to the field of photovoltaic technology, in particular to a photovoltaic control system which comprises a driving unit, a first photovoltaic charging unit, a second photovoltaic charging unit, a battery and a discharging control unit, the first photovoltaic charging unit and the second photovoltaic charging unit are connected in parallel and then connected with the battery, and the discharging control unit comprises first to seventh MOS transistors and a first inductor. The first MOS tube and the second MOS tube are connected in parallel and then connected with the third MOS tube in series to form a first bridge arm, the fourth MOS tube and the fifth MOS tube are connected in parallel, the sixth MOS tube and the seventh MOS tube are connected in parallel and then connected with the fourth MOS tube and the fifth MOS tube in series to form a second bridge arm, and the midpoint of the first bridge arm and the midpoint of the second bridge arm are connected with the two ends of the first inductor respectively. Drain electrodes of the first MOS tube and the second MOS tube are connected with a battery and output ends of the first photovoltaic charging unit and the second photovoltaic charging unit, drain electrodes of the fourth MOS tube and the fifth MOS tube are connected with an inverter, and the driving unit is connected with driving ends of the first bridge arm and the second bridge arm. The circuit board space can be reduced, and the overall cost is reduced.

Description

Technical Field

[0001] The present invention relates to the field of photovoltaic technology, in particular to a photovoltaic control system. Background Art

[0002] The photovoltaic control system is the core component of the photovoltaic power generation system, and its performance directly affects the power generation efficiency and cost of the entire system.

[0003] Existing photovoltaic control systems feature two photovoltaic inputs and two discharge control circuit outputs, each connected to two inverters to achieve high power output. However, achieving high power output requires two discharge control circuits, which requires significant circuit board space and two inverters, resulting in high overall costs. Summary of the Invention

[0004] The technical problem to be solved by the embodiments of the present invention is to provide a photovoltaic control system to solve the problem that the existing photovoltaic control system requires two discharge control circuits to achieve higher power output, which requires a larger circuit board space and requires the use of two inverters, resulting in higher overall costs.

[0005] The present invention discloses a photovoltaic control system, comprising a drive unit, a first photovoltaic charging unit, a second photovoltaic charging unit, a battery, and a discharge control unit. The first photovoltaic charging unit and the second photovoltaic charging unit are connected in parallel to the battery. The discharge control unit comprises a first MOS transistor, a second MOS transistor, a third MOS transistor, a fourth MOS transistor, a fifth MOS transistor, a sixth MOS transistor, a seventh MOS transistor, and a first inductor. The first MOS transistor and the second MOS transistor are connected in parallel and then connected in series with the third MOS transistor to form a first bridge arm. The fourth MOS transistor and the fifth MOS transistor are connected in parallel. The sixth MOS transistor and the seventh MOS transistor are connected in parallel and then connected in series with the fourth MOS transistor and the fifth MOS transistor to form a second bridge arm. The midpoint of the first bridge arm and the midpoint of the second bridge arm are respectively connected to the two ends of the first inductor. The drains of the first and second MOS transistors are connected to the output ends of the battery, the first and second photovoltaic charging units, and the drains of the fourth and fifth MOS transistors are connected to an inverter. The drive unit is connected to the driving ends of the first and second bridge arms.

[0006] Optionally, the discharge control unit includes a discharge current sampling chip, a first current conversion module, a discharge protection module and a main control chip. The positive input end of the discharge current sampling chip is connected to one end of the first inductor, and the negative input end is connected to the midpoint of the second bridge arm. The discharge current sampling chip is used to collect the discharge current of the discharge control unit. The first current conversion module is used to convert the discharge current into a first voltage and transmit it to the discharge protection module and the main control chip. The main control chip outputs a first PWM signal to the discharge protection module according to the first voltage. The discharge protection module is used to output a first drive signal to the drive unit based on the first voltage and the first PWM signal. The drive unit drives the first bridge arm and the second bridge arm to operate according to the first drive signal.

[0007] Optionally, the first current conversion module includes an operational amplifier, a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor and a sixth resistor, the first resistor being connected in series between the output terminal of the discharge current sampling chip and the inverting input terminal of the operational amplifier, the second resistor being connected in series between the voltage reference pin of the discharge current sampling chip and the non-inverting input terminal of the operational amplifier, the third resistor being connected in series between the positive input terminal and the ground terminal of the operational amplifier, the fourth resistor being connected in series between the inverting input terminal and the output terminal of the operational amplifier, the fifth resistor and the sixth resistor being connected in series, with the series node being connected to the input terminal of the discharge protection module, the other end of the fifth resistor being connected to the output terminal of the operational amplifier, and the other end of the sixth resistor being connected to a power supply.

[0008] Optionally, the discharge protection module includes a comparator, a Schmitt trigger inverter and an AND gate, the inverting input terminal of the comparator is connected to the series node of the fifth resistor and the sixth resistor, the positive input terminal is used to input a reference protection voltage, the output terminal is connected to the clear pin of the Schmitt trigger inverter, the clock input pin of the Schmitt trigger inverter is connected to the main control chip to receive a first drive signal, the positive output terminal and the inverting output terminal of the Schmitt trigger inverter are respectively connected to the two input terminals of the AND gate, and the output terminal of the AND gate is connected to the drive unit.

[0009] Optionally, the discharge control unit also includes a load voltage sampling module connected to the main control chip, wherein the load voltage sampling module is used to collect the load voltage and transmit it to the main control chip, and the main control chip is also used to adjust the duty cycle of the first PWM signal according to the load voltage and the first voltage.

[0010] Optionally, the first photovoltaic charging unit and the second photovoltaic charging unit both include a photovoltaic, a relay, an eighth MOS tube, a ninth MOS tube and a second inductor. The relay is arranged between the photovoltaic and the drain of the eighth MOS tube. The eighth MOS tube and the ninth MOS tube are connected in series, and the series node is connected to one end of the second inductor. The source of the ninth MOS tube is grounded, and the other end of the second inductor is connected to the battery, the drain of the first MOS tube and the second MOS tube. The driving ends of the eighth MOS tube and the ninth MOS tube are connected to the driving unit.

[0011] Optionally, the first photovoltaic charging unit and the second photovoltaic charging unit each further include a charging current sampling chip, a second current conversion module and a charging protection module. The charging current sampling chip is used to collect the photovoltaic charging current and transmit it to the second current conversion module. The second current conversion module is used to convert the photovoltaic charging current into a second voltage and transmit it to the main control chip and the charging protection module. The main control chip is also used to output a second PWM signal to the charging protection module according to the second voltage. The charging protection module outputs a second drive signal to the drive unit based on the second voltage and the second PWM signal. The drive unit drives the eighth MOS tube and the ninth MOS tube to operate according to the second drive signal.

[0012] Optionally, the first photovoltaic charging unit and the second photovoltaic charging unit both further include a photovoltaic voltage sampling module connected to the main control chip, wherein the photovoltaic voltage sampling module is used to collect the photovoltaic voltage and transmit it to the main control chip, and the main control chip is further used to adjust the duty cycle of the second PWM signal according to the charging voltage and the second voltage.

[0013] Optionally, the driving unit includes a driving buffer and a driving chip connected to the output end of the driving buffer, the driving buffer is used to receive a PWM signal and amplify and buffer the PWM signal before transmitting it to the driving chip, and the driving chip is used to drive the operation of the first bridge arm and the second bridge arm.

[0014] Optionally, the photovoltaic control system further includes a communication unit, and the communication unit is used to communicate with an external terminal.

[0015] Compared with the prior art, the photovoltaic control system provided by the embodiment of the present invention has the following beneficial effects: the photovoltaic control system provided by the embodiment of the present invention realizes two-way photovoltaic input by setting a first photovoltaic charging unit and a second photovoltaic charging unit in parallel and then connecting them to the input end of the battery and the discharge control unit. The discharge control unit uses a first bridge arm, a second bridge arm and a first inductor to realize discharge control. The first bridge arm of the discharge control unit uses a first MOS tube and a second MOS tube connected in parallel and then in series with a third MOS tube, and the second bridge arm uses two MOS tubes connected in parallel and then in series. This circuit layout can effectively increase the output current of the discharge control unit and realize a higher power output. Therefore, under the same higher output power requirement, the present application uses one discharge control unit to reduce the circuit board space, and the output can use one inverter, which can reduce the overall cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments, in which:

[0017] Figure 1 This is a structural block diagram of a photovoltaic control system provided by an embodiment of the present invention;

[0018] Figure 2 is a circuit schematic diagram of a discharge control unit provided by an embodiment of the present invention;

[0019] Figure 3 is a structural block diagram of a discharge control unit provided by an embodiment of the present invention;

[0020] Figure 4 This is a circuit schematic diagram of the main control chip provided by an embodiment of the present invention;

[0021] Figure 5 is a circuit schematic diagram of a first current conversion module provided by an embodiment of the present invention;

[0022] Figure 6 is a circuit schematic diagram of a discharge protection module provided in an embodiment of the present invention;

[0023] Figure 7 is a circuit schematic diagram of a driving buffer provided by an embodiment of the present invention;

[0024] Figure 8 is a circuit schematic diagram of a driver chip provided by an embodiment of the present invention;

[0025] Figure 9 is a circuit schematic diagram of a load voltage sampling module provided by an embodiment of the present invention;

[0026] Figure 10 is a circuit schematic diagram of a first photovoltaic charging unit provided by an embodiment of the present invention;

[0027] Figure 11 This is a structural block diagram of a first photovoltaic charging unit provided by an embodiment of the present invention;

[0028] Figure 12 This is a partial circuit schematic diagram of a photovoltaic voltage sampling module provided by an embodiment of the present invention;

[0029] Figure 13 This is a partial circuit schematic diagram of a communication unit provided by an embodiment of the present invention.

[0030] The reference numerals in the figures are:

[0031] 110, drive unit; 120, first photovoltaic charging unit; 121, second current conversion module; 122, charging protection module; 123, photovoltaic voltage sampling module; 130, second photovoltaic charging unit; 140, battery; 150, discharge control unit; 151, first current conversion module; 152, discharge protection module; 153, load voltage sampling module; 160, inverter; 170, communication unit;

[0032] Q1, first MOS tube; Q2, second MOS tube; Q3, third MOS tube; Q4, fourth MOS tube; Q5, fifth MOS tube; Q6, sixth MOS tube; Q7, seventh MOS tube; Q8, eighth MOS tube; Q9, ninth MOS tube; L1, first inductor; L2, second inductor; U1, discharge current sampling chip; U2, main control chip; U3, operational amplifier; R1, first resistor; R2, second resistor; R3, third resistor; R4, fourth resistor; R5, fifth resistor; R6, sixth resistor; U4, comparator; U5, Schmitt trigger inverter; U6, AND gate; PV1, photovoltaic; K1, relay; U6, charging current sampling chip; U7, driver buffer; U8, driver chip. DETAILED DESCRIPTION

[0033] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in this application can be combined with each other. Now, in conjunction with the accompanying drawings, the preferred embodiments of the present invention will be described in detail.

[0034] The embodiment of the present invention provides a photovoltaic control system, such as Figure 1 and Figure 2As shown, the photovoltaic control system includes a drive unit 110, a first photovoltaic charging unit 120, a second photovoltaic charging unit 130, a battery 140 and a discharge control unit 150. The first photovoltaic charging unit 120 and the second photovoltaic charging unit 130 are connected in parallel and then connected to the battery 140. The discharge control unit 150 includes a first MOS transistor Q1, a second MOS transistor Q2, a third MOS transistor Q3, a fourth MOS transistor Q4, a fifth MOS transistor Q5, a sixth MOS transistor Q6, a seventh MOS transistor Q7 and a first inductor L1. The first MOS transistor Q1 and the second MOS transistor Q2 are connected in parallel and then connected in series with the third MOS transistor Q3 to form a first In the bridge arm, the fourth MOS transistor Q4 and the fifth MOS transistor Q5 are connected in parallel, and the sixth MOS transistor Q6 and the seventh MOS transistor Q7 are connected in parallel and then connected in series with the fourth MOS transistor Q4 and the fifth MOS transistor Q5 to form a second bridge arm. The midpoint of the first bridge arm and the midpoint of the second bridge arm are respectively connected to the two ends of the first inductor L1. The drains of the first MOS transistor Q1 and the second MOS transistor Q2 are connected to the output ends of the battery 140 and the first photovoltaic charging unit 120 and the second photovoltaic charging unit 130. The drains of the fourth MOS transistor Q4 and the fifth MOS transistor Q5 are connected to the inverter 160. The drive unit 110 is connected to the drive ends of the first bridge arm and the second bridge arm.

[0035] The photovoltaic control system provided in the embodiment of the present invention realizes two-way photovoltaic PV1 input by setting a first photovoltaic charging unit 120 and a second photovoltaic charging unit 130 in parallel and then connecting them to the input end of the battery 140 and the discharge control unit 150. The discharge control unit 150 uses the first bridge arm and the second bridge arm in combination with the first inductor L1 to realize discharge control. The first bridge arm of the discharge control unit 150 uses the first MOS tube Q1 and the second MOS tube Q2 in parallel and then in series with the third MOS tube Q3. The second bridge arm uses two MOS tubes connected in parallel and then in series. This circuit layout can effectively increase the output current of the discharge control unit 150 and realize higher power output. Therefore, under the same higher output power requirement, the present application uses one discharge control unit 150 to reduce circuit board space, and the output uses one inverter 160, which can reduce overall cost.

[0036] The first photovoltaic charging unit 120 can supply power to the inverter 160 via the discharge control unit 150. The second photovoltaic charging unit 130 can also supply power to the inverter 160 via the discharge control unit 150. The battery 140 can also supply power to the inverter 160 via the discharge control unit 150. Both the first photovoltaic charging unit 120 and the second photovoltaic charging unit 130 can charge the battery 140, and the charging operations of the two are completely independent.

[0037] In the first bridge arm and the second bridge arm, the two MOS tubes connected in parallel can increase the driving current. At the same time, when one of the MOS tubes is damaged, the other MOS tube can also ensure the normal operation of the circuit. The two MOS tubes connected in parallel can also disperse heat, reduce the temperature of each MOS tube, and ensure the long-term operation of the photovoltaic control system. The conduction loss is also low, and it supports the buck-boost seamless mode switching. Compared with the existing buck-boost circuit for powering the inverter 160, such as the SEPIC circuit (single-ended primary inductor converter) and the flyback circuit, the discharge control unit 150 of the present application has higher efficiency and power, and allows a wide input voltage range, supporting input voltages higher than, lower than or equal to the output voltage.

[0038] During specific operation, the first MOS transistor Q1, the second MOS transistor Q2, the seventh MOS transistor Q7, and the eighth MOS transistor Q8 are turned on, and the third MOS transistor Q3, the fifth MOS transistor Q5, and the sixth MOS transistor Q6 are turned off, and the first inductor L1 begins to be charged. After a period of time, the first MOS transistor Q1, the second MOS transistor Q2, the seventh MOS transistor Q7, and the eighth MOS transistor Q8 are turned off, and the third MOS transistor Q3, the fifth MOS transistor Q5, and the sixth MOS transistor Q6 are turned on. The first inductor L1 releases electrical energy to the load, and power is supplied to the load through the inverter 160. The above process is repeated to achieve voltage boosting, and the output is supplied to the power supply device through the inverter 160.

[0039] refer to Figure 3 In an optional embodiment of the present application, the discharge control unit 150 includes a discharge current sampling chip U1, a first current conversion module 151, a discharge protection module 152, and a main control chip U2. The positive input terminal of the discharge current sampling chip U1 is connected to one end of the first inductor L1, and the negative input terminal is connected to the midpoint of the second bridge arm. The discharge current sampling chip U1 is used to collect the discharge current of the discharge control unit 150. The first current conversion module 151 is used to convert the discharge current into a first voltage and transmit it to the discharge protection module 152 and the main control chip U2. The main control chip U2 outputs a first PWM signal to the discharge protection module 152 according to the first voltage. The discharge protection module 152 is used to output a first drive signal to the drive unit 110 based on the first voltage and the first PWM signal. The drive unit 110 drives the first bridge arm and the second bridge arm according to the first drive signal.

[0040] Specifically, the discharge current sampling chip U1 can sample and obtain the discharge current of the discharge control unit 150. Compared with the existing differential current sampling method, the discharge current sampling chip U1 has the characteristics of high sensitivity, low noise, low offset drift and gain drift, etc., and can provide high-precision current measurement and strong anti-interference ability. In this way, overcurrent protection is more accurate and sensitive, reducing the possibility of damage to components, and more accurate calculation of input and output power. Using an isolated power supply reduces interference. The first current conversion module 151 converts the discharge current into a first voltage. The voltage signal is relatively more stable during transmission and has stronger anti-interference ability. Therefore, compared with directly obtaining the discharge current, the main control chip U2 obtains the first voltage and outputs the first PWM signal, making the control of the first bridge arm and the second bridge arm more stable. The discharge protection module 152 is used to output the first drive signal based on the first voltage and the first PWM signal. It can combine hardware and software to implement protection against discharge current anomalies and improve the reliability of the circuit.

[0041] refer to Figure 2 and Figure 5 In an optional embodiment of the present application, the first current conversion module 151 includes an operational amplifier U3, a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, and a sixth resistor R6. The first resistor R1 is connected in series between the output terminal of the discharge current sampling chip U1 and the inverting input terminal of the operational amplifier U3. The second resistor R2 is connected in series between the voltage reference pin of the discharge current sampling chip U1 and the non-inverting input terminal of the operational amplifier U3. The third resistor R3 is connected in series between the positive input terminal and the ground terminal of the operational amplifier U3. The fourth resistor R4 is connected in series between the inverting input terminal and the output terminal of the operational amplifier U3. The fifth resistor R5 and the sixth resistor R6 are connected in series, and the series node is connected to the input terminal of the discharge protection module 152. The other end of the fifth resistor R5 is connected to the output terminal of the operational amplifier U3. The other end of the sixth resistor R6 is connected to the power supply.

[0042] By setting a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5 and a sixth resistor R6 to form a resistor network, combined with an operational amplifier U3, the discharge current can be accurately converted into a voltage signal. This conversion method can provide high-precision current monitoring, ensuring that the system controls the discharge current more accurately.

[0043] Specifically, Figure 5 The voltage at point y is V y , set the current protection value to 0<I P <33, V is obtained by calculation y =0.048*I P +0.3, V y The calculation formula is obtained in the following way:

[0044] According to the virtual short circuit and virtual disconnection principle of the operational amplifier U3, when analyzing the linear state of the operational amplifier U3, the two input terminals can be regarded as equal potential. This characteristic is called a false short circuit, or virtual short for short, that is, V U3A2 =V U3A3 , Among them, R1 to R4 are the resistance values ​​of the first resistor R1 to the fourth resistor R4 respectively. When analyzing the linear state of the operational amplifier, the two input terminals can be regarded as equivalent open circuits. This characteristic is called false open circuit, or virtual disconnection for short. That is, the current flowing through the second resistor R2 is equal to the current flowing through the third resistor R3, and the current flowing through the first resistor R1 and the fourth resistor R4 are equal. We can get Figure 5 Voltage at point x And R1=R3, R1=R2, where, and are the voltages input by the first resistor R1 and the second resistor R2 respectively. The voltage at point x is simplified to The function of the discharge current sampling chip U1 is to collect the current I P The relationship between the voltage difference and the discharge current is Rate_V_I = 0.016, where Rate_V_I is the current I collected by the discharge current sampling chip U1. P The relationship with the pressure difference, so Substitute Rate_V_I=0.016 into the calculation to get V x =0.0528*I P , the voltage at point y is V y By the superposition theorem, we can get Among them, V 3.3 For the power supply voltage, V 3.3 and V x Substituting into V y =0.048*I P +0.3, if the current protection value is 0<I P <33, then the voltage at point y is 0.3<V y <1.88, that is, under normal discharge current conditions, the first voltage converted by the first current conversion module 151 is less than 1.88V.

[0045] Further, refer to Figures 4 to 6The discharge protection module 152 includes a comparator U4, a Schmitt trigger inverter U5, and an AND gate U6. The inverting input terminal of the comparator U4 is connected to the series node of the fifth resistor R5 and the sixth resistor R6, the positive input terminal is used to input the reference protection voltage, the output terminal is connected to the clear pin 1CLR of the Schmitt trigger inverter U5, the clock input pin 1CLK of the Schmitt trigger inverter U5 is connected to the main control chip U2 to receive the first drive signal, the non-inverting output terminal and the inverting output terminal of the Schmitt trigger inverter U5 are respectively connected to the two input terminals of the AND gate U6, and the output terminal of the AND gate U6 is connected to the drive unit 110.

[0046] The inverting input of comparator U4 is connected to the output node of the first current conversion module 151, and the positive input receives a reference protection voltage. This design accurately compares the discharge voltage corresponding to the actual discharge current with the set protection voltage, indirectly comparing the detected discharge current with the set protection current. When the discharge current is abnormal, the output of comparator U4 outputs a low level. That is, when the first voltage converted by the first current conversion module 151 is greater than 1.88V, the output of comparator U4 outputs a low level. The clock input pin 1CLK of the Schmitt trigger inverter U5 receives the first drive signal from the main control chip U2 and can synchronize the first drive signal. When the clear pin 1CLR of the Schmitt trigger inverter U5 receives a low level, the AND gate U6 outputs a 0, no first drive signal is output, and the MOS transistors of the first and second bridge arms are in the off state. When the output of comparator U4 outputs a high level, the clear pin 1CLR of the Schmitt trigger inverter U5 receives a high level, and the first drive signal is output normally.

[0047] refer to Figure 3 In an optional embodiment of the present application, the discharge control unit 150 also includes a load voltage sampling module 153 connected to the main control chip U2. The load voltage sampling module 153 is used to collect the load voltage and transmit it to the main control chip U2. The main control chip U2 is also used to adjust the duty cycle of the first PWM signal according to the load voltage and the first voltage.

[0048] By setting up a load voltage sampling module 153, the load voltage is collected and fed back to the main control chip U2. The main control chip U2 dynamically adjusts the duty cycle of the first PWM signal according to the actual load voltage and discharge current, thereby accurately controlling the output voltage, optimizing the power supply to the load, and optimizing the energy conversion efficiency of the system. For example, when the load changes, by adjusting the duty cycle, energy loss can be reduced, and the efficiency of the entire photovoltaic control system can be improved. The main control chip U2 is allowed to combine the maximum power point tracking (MPPT, Maximum Power Point Tracking) algorithm to dynamically adjust the duty cycle of the first PWM signal according to the output characteristics and load requirements of the photovoltaic PV1 and the battery 140 to achieve maximum power output. The circuit schematic diagram of the load voltage sampling module 153 is shown in FIG. Figure 9 shown.

[0049] refer to Figure 10 In an optional embodiment of the present application, the first photovoltaic charging unit 120 and the second photovoltaic charging unit 130 each include a photovoltaic cell PV1, a relay K1, an eighth MOS transistor Q8, a ninth MOS transistor Q9, and a second inductor L2. The relay K1 is disposed between the photovoltaic cell PV1 and the drain of the eighth MOS transistor Q8. The eighth MOS transistor Q8 and the ninth MOS transistor Q9 are connected in series, with the series node connected to one end of the second inductor L2. The source of the ninth MOS transistor Q9 is grounded. The other end of the second inductor L2 is connected to the battery 140 and the drains of the first MOS transistor Q1 and the second MOS transistor Q2. The driving ends of the eighth MOS transistor Q8 and the ninth MOS transistor Q9 are connected to the driving unit 110.

[0050] Specifically, the eighth MOS transistor Q8, the ninth MOS transistor Q9, and the second inductor L2 combine to form a simple step-down circuit with a simple circuit structure. A relay K1 is used to connect or disconnect the path between the photovoltaic cell PV1 and the step-down circuit. Compared to a MOS transistor, the relay K1 can completely disconnect the photovoltaic cell PV1 from the step-down circuit, providing better protection in the event of a fault. Furthermore, the drive circuit for the relay K1 is simple.

[0051] During the charging process of the battery 140 , the eighth MOS transistor Q8 receives a high level and is turned on, and the ninth MOS transistor Q9 receives a low level and is turned off. After a period of time, the eighth MOS transistor Q8 receives a low level and is turned off, and the ninth MOS transistor Q9 receives a high level and is turned on for freewheeling, and the above process is repeated.

[0052] refer to Figure 10 and Figure 11In an optional embodiment of the present application, the first photovoltaic charging unit 120 and the second photovoltaic charging unit 130 each further include a charging current sampling chip U6, a second current conversion module 121, and a charging protection module 122. The charging current sampling chip U6 is used to collect the photovoltaic charging current and transmit it to the second current conversion module 121. The second current conversion module 121 is used to convert the photovoltaic charging current into a second voltage and transmit it to the main control chip U2 and the charging protection module 122. The main control chip U2 is further used to output a second PWM signal to the charging protection module 122 based on the second voltage. The charging protection module 122 outputs a second drive signal to the drive unit 110 based on the second voltage and the second PWM signal. The drive unit 110 drives the eighth MOS transistor Q8 and the ninth MOS transistor Q9 according to the second drive signal.

[0053] Specifically, the photovoltaic charging current is collected by the charging current sampling chip U6 and transmitted to the second current conversion module 121. This real-time monitoring function ensures accurate measurement of the charging current, providing accurate data support for the main control chip U2. Accurate current monitoring enables the system to dynamically adjust according to the actual charging current, avoiding overcharging or undercharging, thereby extending the life of the battery 140. The second current conversion module 121 converts the charging current into a second voltage, making the current signal easier to process and transmit while reducing signal interference. The main control chip U2 outputs a second PWM signal to the charging protection module 122 based on the second voltage. This dynamic adjustment capability enables the charging process to be optimized based on the actual state of the battery 140, for example, reducing the charging current when the battery 140 is nearly fully charged to avoid overcharging. The charging protection module 122 outputs a second drive signal to the drive unit 110 based on the second voltage and the second PWM signal. The second drive signal can be output to the drive unit 110 through a combination of hardware and software. In the event of abnormal current flow, the control of the main control chip U2 fails, and the circuit protection function can also be implemented.

[0054] In an optional embodiment of the present application, the circuit structure of the second current conversion module 121 is the same as that of the first current conversion module 151, and is not described in detail here. The circuit structure of the charging protection module 122 is the same as that of the discharging protection module 152, and is not described in detail here.

[0055] refer to Figure 11 and Figure 12 In an optional embodiment of the present application, the first photovoltaic charging unit 120 and the second photovoltaic charging unit 130 also include a photovoltaic voltage sampling module 123 connected to the main control chip U2. The photovoltaic voltage sampling module 123 is used to collect the photovoltaic voltage and transmit it to the main control chip U2. The main control chip U2 is also used to adjust the duty cycle of the second PWM signal according to the photovoltaic voltage and the second voltage.

[0056] By setting up a photovoltaic voltage sampling module 123, the photovoltaic voltage is collected and fed back to the main control chip U2. The main control chip U2 dynamically adjusts the duty cycle of the second PWM signal according to the actual photovoltaic voltage and charging current, thereby accurately controlling the charging of the battery 140 and optimizing the energy conversion efficiency of the system. For example, when the battery 140 changes, the duty cycle can be adjusted to reduce energy loss and improve the efficiency of the entire photovoltaic control system. The main control chip U2 is allowed to combine the maximum power point tracking (MPPT) algorithm to dynamically adjust the duty cycle of the second PWM signal according to the output characteristics and load requirements of the photovoltaic PV1 and the battery 140 to achieve maximum power output for charging the battery 140.

[0057] The two photovoltaic charging units charge the battery 140 completely independently and can each track the MPPT maximum charging point of the photovoltaic PV1.

[0058] The photovoltaic voltage sampling module 123 can sample and obtain the photovoltaic voltage. The circuit schematic diagram is as follows: Figure 12 shown.

[0059] refer to Figure 2 、 Figure 7 and Figure 8 In an optional embodiment of the present application, the driving unit 110 includes a driving buffer U7 and a driving chip U8 connected to the output end of the driving buffer U7. The driving buffer U7 is used to receive a PWM signal and amplify and buffer the PWM signal before transmitting it to the driving chip U8. The driving chip U8 is used to drive the operation of the first bridge arm and the second bridge arm.

[0060] By amplifying and buffering the input signal, driver buffer U7 effectively mitigates signal attenuation and distortion, ensuring accurate and efficient signal transmission to driver chip U8 and improving signal transmission reliability. Driver chip U8 receives the amplified and buffered PWM signal and converts it into a drive signal capable of driving the first and second bridge arms. Driver chip U8 typically has higher drive capability and can directly control the MOSFET, turning it on and off. The schematic diagram of driver buffer U7 is shown in the figure. The schematic diagram of driver chip U8 is shown in the figure.

[0061] refer to Figure 1 In an optional embodiment of the present application, the photovoltaic control system further includes a communication unit 170, and the communication unit 170 is used to communicate with an external terminal.

[0062] By setting up the communication unit 170, a communication connection with an external terminal can be achieved, and remote monitoring and management of the photovoltaic control system can be realized. Such a setting allows users to monitor the operating status of the system anytime and anywhere, perform remote operations and adjustments, and improve the operability and convenience of the system. The communication unit 170 can transmit system operation data and fault information to the external terminal to help users find problems and diagnose them in time. Through remote monitoring and diagnosis, the cause of the fault can be quickly located, maintenance time can be reduced, and the reliability and stability of the system can be improved. The communication unit 170 can also realize the data acquisition function, and transmit the system operation data to the external terminal for analysis and processing. Through the analysis of the data, the user can optimize the system operation strategy and improve the efficiency and performance of the system. The circuit schematic diagram of the communication unit 170 is shown in the figure. Figure 13 The communication unit 170 also allows the user to set the output power of the discharge control unit 150 through the terminal APP.

[0063] The photovoltaic control system of the embodiment of the present application can be used on balconies, or in scenes such as street lights and fish ponds.

[0064] It should be understood that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Those skilled in the art may modify the technical solutions described in the above embodiments, or make equivalent replacements for some of the technical features therein; and all these modifications and replacements should fall within the scope of protection of the claims attached to the present invention.

Claims

1. A photovoltaic control system, characterized in that: The invention comprises a driving unit, a first photovoltaic charging unit, a second photovoltaic charging unit, a battery and a discharge control unit. The first photovoltaic charging unit and the second photovoltaic charging unit are connected in parallel to the battery. The discharge control unit comprises a first MOS transistor, a second MOS transistor, a third MOS transistor, a fourth MOS transistor, a fifth MOS transistor, a sixth MOS transistor, a seventh MOS transistor and a first inductor. The first MOS transistor and the second MOS transistor are connected in parallel and then in series with the third MOS transistor to form a first bridge arm. The fourth MOS transistor and the fifth MOS transistor are connected in parallel. The sixth MOS transistor and the seventh MOS transistor are connected in parallel and then in series with the fourth MOS transistor and the fifth MOS transistor to form a second bridge arm. The midpoint of the first bridge arm and the midpoint of the second bridge arm are respectively connected to the two ends of the first inductor. The drains of the first MOS transistor and the second MOS transistor are connected to the output ends of the battery, the first photovoltaic charging unit and the second photovoltaic charging unit. The drains of the fourth MOS transistor and the fifth MOS transistor are connected to an inverter. The driving unit is connected to the driving ends of the first bridge arm and the second bridge arm.

2. The photovoltaic control system according to claim 1, characterized in that: The discharge control unit includes a discharge current sampling chip, a first current conversion module, a discharge protection module, and a main control chip. The positive input terminal of the discharge current sampling chip is connected to one end of the first inductor, and the negative input terminal is connected to the midpoint of the second bridge arm. The discharge current sampling chip is used to collect the discharge current of the discharge control unit. The first current conversion module is used to convert the discharge current into a first voltage and transmit it to the discharge protection module and the main control chip. The main control chip outputs a first PWM signal to the discharge protection module based on the first voltage. The discharge protection module is used to output a first drive signal to the drive unit based on the first voltage and the first PWM signal. The drive unit drives the first bridge arm and the second bridge arm to operate according to the first drive signal.

3. The photovoltaic control system according to claim 2, characterized in that: The first current conversion module includes an operational amplifier, a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, and a sixth resistor. The first resistor is connected in series between the output terminal of the discharge current sampling chip and the inverting input terminal of the operational amplifier. The second resistor is connected in series between the voltage reference pin of the discharge current sampling chip and the non-inverting input terminal of the operational amplifier. The third resistor is connected in series between the positive input terminal and the ground terminal of the operational amplifier. The fourth resistor is connected in series between the inverting input terminal and the output terminal of the operational amplifier. The fifth resistor and the sixth resistor are connected in series, and the series node is connected to the input terminal of the discharge protection module. The other end of the fifth resistor is connected to the output terminal of the operational amplifier. The other end of the sixth resistor is connected to the power supply.

4. The photovoltaic control system according to claim 3, characterized in that: The discharge protection module includes a comparator, a Schmitt trigger inverter and an AND gate. The inverting input terminal of the comparator is connected to the series node of the fifth resistor and the sixth resistor, the positive input terminal is used to input a reference protection voltage, the output terminal is connected to the clear pin of the Schmitt trigger inverter, the clock input pin of the Schmitt trigger inverter is connected to the main control chip to receive a first drive signal, the non-phase output terminal and the inverting output terminal of the Schmitt trigger inverter are respectively connected to the two input terminals of the AND gate, and the output terminal of the AND gate is connected to the drive unit.

5. The photovoltaic control system according to claim 2, characterized in that: The discharge control unit also includes a load voltage sampling module connected to the main control chip, the load voltage sampling module is used to collect the load voltage and transmit it to the main control chip, and the main control chip is also used to adjust the duty cycle of the first PWM signal according to the load voltage and the first voltage.

6. The photovoltaic control system according to claim 1, characterized in that: The first photovoltaic charging unit and the second photovoltaic charging unit each include a photovoltaic, a relay, an eighth MOS transistor, a ninth MOS transistor, and a second inductor. The relay is arranged between the photovoltaic and the drain of the eighth MOS transistor. The eighth MOS transistor and the ninth MOS transistor are connected in series, and the series node is connected to one end of the second inductor. The source of the ninth MOS transistor is grounded. The other end of the second inductor is connected to the battery, the drains of the first MOS transistor, and the second MOS transistor. The driving ends of the eighth MOS transistor and the ninth MOS transistor are connected to the driving unit.

7. The photovoltaic control system according to claim 6, characterized in that: The first photovoltaic charging unit and the second photovoltaic charging unit each further include a charging current sampling chip, a second current conversion module, and a charging protection module. The charging current sampling chip is used to collect the photovoltaic charging current and transmit it to the second current conversion module. The second current conversion module is used to convert the photovoltaic charging current into a second voltage and transmit it to the main control chip and the charging protection module. The main control chip is further used to output a second PWM signal to the charging protection module based on the second voltage. The charging protection module outputs a second drive signal to the drive unit based on the second voltage and the second PWM signal. The drive unit drives the eighth MOS transistor and the ninth MOS transistor to operate according to the second drive signal.

8. The photovoltaic control system according to claim 7, characterized in that: The first photovoltaic charging unit and the second photovoltaic charging unit also include a photovoltaic voltage sampling module connected to the main control chip, the photovoltaic voltage sampling module is used to collect the photovoltaic voltage and transmit it to the main control chip, and the main control chip is also used to adjust the duty cycle of the second PWM signal according to the charging voltage and the second voltage.

9. The photovoltaic control system according to claim 1, characterized in that: The driving unit includes a driving buffer and a driving chip connected to the output end of the driving buffer. The driving buffer is used to receive a PWM signal and amplify and buffer the PWM signal before transmitting it to the driving chip. The driving chip is used to drive the operation of the first bridge arm and the second bridge arm.

10. The photovoltaic control system according to any one of claims 1 to 9, characterized in that: The photovoltaic control system further includes a communication unit, which is used for communication connection with an external terminal.

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