CN109066847B - Photovoltaic power generation charge-discharge control circuit - Google Patents
Photovoltaic power generation charge-discharge control circuit Download PDFInfo
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Abstract
The application provides a photovoltaic power generation charge-discharge control circuit. The application provides photovoltaic power generation charge-discharge control circuit includes: the device comprises a boosting circuit, a switching tube control circuit and a Maximum Power Point Tracking (MPPT) control circuit; the switching tube control circuit is connected with the booster circuit and is used for controlling the charging and discharging state of the booster circuit; the MPPT control circuit is respectively connected with the photovoltaic power supply, the booster circuit and the switching tube control circuit, and is used for collecting the open-circuit voltage of the photovoltaic power supply when the booster circuit is in a discharge state, and adjusting the output voltage of the photovoltaic power supply according to the open-circuit voltage so as to enable the photovoltaic power supply to output with the maximum power. The photovoltaic power generation charge and discharge control circuit provided by the application has low power consumption.
Description
Technical Field
The application relates to the technical field of photovoltaic power generation, in particular to a photovoltaic power generation charge and discharge control circuit.
Background
Solar energy is widely favored as an inexhaustible clean energy source. The solar photovoltaic power generation technology is a novel power generation technology which directly converts solar radiation energy into electric energy by mainly utilizing the photovoltaic effect of a solar cell. However, the output power of the solar cell (i.e., the photovoltaic power supply) varies with the ambient temperature and the illumination intensity, and exhibits a nonlinear characteristic. Therefore, how to increase the output power of the solar cell becomes an important link of photovoltaic power generation.
At present, a photovoltaic power generation charge-discharge controller is often adopted to maximize the output power of a solar battery. Fig. 1 is a schematic structural diagram of a photovoltaic power generation charge and discharge controller disclosed in the related art. Referring to fig. 1, the charge and discharge controller for photovoltaic power generation includes a voltage boost circuit and a microcontroller, wherein an input terminal of the voltage boost circuit is connected to an output terminal of a photovoltaic power supply, and an output terminal of the voltage boost circuit is connected to an energy storage element (for example, the energy storage element may be a lithium battery); the microcontroller is mainly used for detecting the output voltage and the output current of the photovoltaic Power supply, and further controlling the duty ratio of a Pulse Width Modulation (PWM) signal input to the control end of the boost circuit by using an mppt (maximum Power Point tracking) control algorithm (for example, by using a disturbance observation method) according to the detected output voltage and output current, so as to achieve the purpose of changing the output voltage and output current of the photovoltaic Power supply, and enable the photovoltaic Power supply to output at the maximum Power.
However, the existing photovoltaic power generation charge and discharge controllers are all provided with microcontrollers, and the microcontrollers need to run an MPPT control algorithm to enable the photovoltaic power supply to output the maximum power, so that the power consumption is large.
Disclosure of Invention
In view of this, the present application provides a photovoltaic power generation charge and discharge control circuit to solve the problem that the power consumption of the existing photovoltaic power generation charge and discharge controller is large.
The application provides a photovoltaic power generation charge-discharge control circuit, includes: the device comprises a boosting circuit, a switching tube control circuit and a Maximum Power Point Tracking (MPPT) control circuit; wherein the content of the first and second substances,
the switch tube control circuit is connected with the booster circuit and is used for controlling the charge and discharge state of the booster circuit;
the MPPT control circuit is respectively connected with the photovoltaic power supply, the booster circuit and the switching tube control circuit, and is used for collecting the open-circuit voltage of the photovoltaic power supply when the booster circuit is in a discharge state, and adjusting the output voltage of the photovoltaic power supply according to the open-circuit voltage so as to enable the photovoltaic power supply to output with the maximum power.
The application provides a photovoltaic power generation charge-discharge control circuit, through setting up switch tube control circuit and MPPT control circuit, and then through switch tube control circuit control boost circuit's charge-discharge state, when boost circuit is in discharge state through the MPPT control circuit, gather photovoltaic power's open circuit voltage to adjust photovoltaic power's output voltage according to open circuit voltage, so that photovoltaic power exports with maximum power. Therefore, the analog circuit replaces the microcontroller, the photovoltaic power supply is output at the maximum power, the microcontroller is not needed, the MPPT algorithm is not needed, the photovoltaic power supply can be output at the maximum power, and the power consumption can be reduced.
Drawings
Fig. 1 is a schematic structural diagram of a photovoltaic power generation charge and discharge controller disclosed in the related art;
fig. 2 is a schematic diagram of a first embodiment of a photovoltaic power generation charge and discharge control circuit provided in the present application;
FIG. 3 is an I-V characteristic of a photovoltaic power source shown in an exemplary embodiment of the present application;
fig. 4 is a schematic diagram of a second embodiment of a photovoltaic power generation charge-discharge control circuit provided in the present application;
FIG. 5 is a schematic diagram of a PWM signal generating circuit of the circuit of FIG. 4 according to an exemplary embodiment of the present application;
fig. 6 is a schematic diagram of a third embodiment of a photovoltaic power generation charge and discharge control circuit provided in the present application;
FIG. 7 is a schematic diagram of a PWM signal generating circuit in the circuit of FIG. 6 according to an exemplary embodiment of the present application;
fig. 8 is a graph illustrating brightness characteristics of a photovoltaic power source according to an exemplary embodiment of the present application.
Description of reference numerals:
1: a boost circuit;
11: an inductor in the boost circuit;
12: a diode in the boost circuit;
121: an anode of the diode;
122: a cathode of the diode;
13: a capacitor in the boost circuit;
14: a first switch tube in the booster circuit;
15: a fourth switching tube in the booster circuit;
2: a switch tube control circuit;
21: a logic circuit;
211: a first AND gate;
212: a second AND gate;
22: a PWM signal generating circuit;
221: an error amplifier;
222: an I/V conversion circuit;
223: a PWM comparator;
224: a logic chip;
225: an overcurrent protection circuit;
2251: an overcurrent comparator;
2252: a second switching tube;
2253: a third switching tube;
A. b: an input terminal of a PWM signal generating circuit;
c: a PWM signal output end of the PWM signal generating circuit;
d: the control ends of the second switching tube and the third switching tube;
3: an MPPT control circuit;
31: a clock circuit;
311: an output terminal of the clock circuit;
32: a sampling circuit;
321: a control signal input end of the sampling circuit;
322: an analog signal input end of the sampling circuit;
323: an analog signal output end of the sampling circuit;
33: a proportional circuit;
331: an input terminal of the proportional circuit;
332: an output of the proportional circuit;
34: an operational amplifier circuit;
341: a non-inverting input of the operational amplifier circuit;
342: an inverting input of the operational amplifier circuit;
343: an output terminal of the operational amplifier circuit;
35: a voltage comparator;
351: the non-inverting input end of the voltage comparator;
352: an inverting input of the voltage comparator;
353: an output terminal of the voltage comparator;
4: a photovoltaic power source;
5: an energy storage element;
6: a first reference power supply;
7: a second reference power supply;
8: a third reference power supply;
9: a voltage dividing circuit;
r1: a first resistor;
r2: a second resistor;
r3: and a third resistor.
Detailed Description
Reference will now be made in detail to the exemplary embodiments, examples of which are illustrated in the accompanying drawings. When the following description refers to the accompanying drawings, like numbers in different drawings represent the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present application. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the present application, as detailed in the appended claims.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used in this application and the appended claims, the singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It should also be understood that the term "and/or" as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items.
It is to be understood that although the terms first, second, third, etc. may be used herein to describe various information, such information should not be limited to these terms. These terms are only used to distinguish one type of information from another. For example, first information may also be referred to as second information, and similarly, second information may also be referred to as first information, without departing from the scope of the present application. The word "if" as used herein may be interpreted as "at … …" or "when … …" or "in response to a determination", depending on the context.
The application provides a photovoltaic power generation charge and discharge control circuit to solve the great problem of current photovoltaic power generation charge and discharge controller consumption.
Several specific embodiments are given below to describe the technical solutions of the present application in detail, and these specific embodiments may be combined with each other, and details of the same or similar solutions or processes may not be repeated in some embodiments.
Fig. 2 is a schematic diagram of a first embodiment of a photovoltaic power generation charge and discharge control circuit provided in the present application. Referring to fig. 2, the photovoltaic power generation charge/discharge control circuit provided in this embodiment includes: the power supply comprises a booster circuit 1, a switching tube control circuit 2 and a maximum power point tracking MPPT control circuit 3; wherein the content of the first and second substances,
the switching tube control circuit 2 is connected with the booster circuit 1 and is used for controlling the charging and discharging state of the booster circuit 1;
Specifically, the specific circuit structure of the boost circuit 1 can be referred to the description in the related art, and is not described herein again. In addition, the switching tube control circuit 2 may be connected to the switching tube of the voltage boost circuit 1 to control the charge and discharge state of the voltage boost circuit 1. For example, when the control switch tube is turned on, the booster circuit 1 is in a charging state; when the control switch tube is cut off, the booster circuit 1 is in a discharging state.
In addition, FIG. 3 is an I-V characteristic of a photovoltaic power source shown in an exemplary embodiment of the present application. Referring to fig. 3, when the output power of the photovoltaic power source reaches the maximum power, the output voltage of the photovoltaic power source is equal to the specified multiple of the open-circuit voltage. Referring to fig. 3, the output voltage of the photovoltaic power supply is equal to 0.8 times its open circuit voltage. Therefore, in the application, the open-circuit voltage of the photovoltaic power supply can be obtained through the analog circuit, and then the output voltage of the photovoltaic power supply is adjusted according to the open-circuit voltage, so that the photovoltaic power supply can output the maximum power. For example, the output voltage of the photovoltaic power supply may be adjusted to 0.8 times its open circuit voltage voc, i.e. the output voltage of the photovoltaic power supply is equal to 0.8 voc. Thus, when the output voltage of the photovoltaic power supply is fixed at 0.8voc, the photovoltaic power supply can only output a current corresponding to the voltage. Referring to fig. 3, in this way, the photovoltaic power source can be made to output at maximum power.
The application provides a photovoltaic power generation charge-discharge control circuit, through setting up switch tube control circuit and MPPT control circuit, and then through switch tube control circuit control boost circuit's charge-discharge state, when boost circuit is in discharge state through the MPPT control circuit, gather photovoltaic power's open circuit voltage to adjust photovoltaic power's output voltage according to open circuit voltage, so that photovoltaic power exports with maximum power. Therefore, the analog circuit replaces the microcontroller, the photovoltaic power supply is output at the maximum power, the microcontroller is not needed, the MPPT algorithm is not needed, the photovoltaic power supply can be output at the maximum power, and the power consumption can be reduced.
Fig. 4 is a schematic diagram of a second embodiment of a photovoltaic power generation charge-discharge control circuit provided in the present application. Referring to fig. 4, based on the above embodiment, in the photovoltaic power generation charge and discharge control circuit provided in this embodiment, the switching tube control circuit 2 includes a logic circuit 21 and a pulse width modulation PWM signal generation circuit 22, wherein an input end of the logic circuit 21 is respectively connected to the MPPT control circuit 3 and the PWM signal generation circuit 22, and an output end of the logic circuit is connected to a control end of the boost circuit 1, and is configured to generate a switching tube control signal for controlling a charge and discharge state of the boost circuit 1 according to a signal from the MPPT control circuit 3 and a PWM signal from the PWM signal generation circuit 22;
the PWM signal generator 22 is further connected to the MPPT control circuit 3 and the boost circuit 1, and configured to generate a PWM signal according to a voltage corresponding to an output voltage of the MPPT control circuit 3 and an output current of the boost circuit 1.
Specifically, referring to fig. 4, in the example shown in fig. 4, the boost circuit includes an inductor 11, a diode 12, a capacitor 13, and a first switching tube 14, and for the operation principle of the boost circuit, reference may be made to the description in the related art, and details are not described here. In the example shown in fig. 4, the first switching transistor 14 is a MOS transistor, and the G electrode of the MOS transistor is the control terminal of the voltage boost circuit 1. Specifically, referring to fig. 4, an input terminal C of the PWM signal generation circuit 22 is connected to the anode 121 of the diode 12 in the booster circuit 1.
Optionally, in the example shown in fig. 4, the MPPT control circuit includes: a clock circuit 31, a sampling circuit 32, a scaling circuit 33, and an operational amplifier circuit 34, wherein,
the output terminal 311 of the clock circuit 31 is connected to the control signal input terminals 321 of the logic circuit 21 and the sampling circuit 32, respectively;
an analog signal input end 322 of the sampling circuit 32 is connected with the photovoltaic power supply 4, and an analog signal output end 323 is connected with an input end 331 of the proportional circuit 33; the sampling circuit 32 is configured to operate in a sampling state when the clock signal generated by the clock circuit 31 is at a low level, and operate in a holding state when the clock signal generated by the clock circuit 31 is at a high level;
the output terminal 332 of the proportional circuit 33 is connected to the non-inverting input terminal 341 of the operational amplifier circuit 34, the inverting input terminal 342 of the operational amplifier circuit 34 is connected to the photovoltaic power source 4, and the output terminal 343 of the operational amplifier circuit 34 is connected to the output terminal of the voltage boost circuit 1 and the PWM signal generation circuit 22, respectively;
the switching tube control circuit 2 is configured to generate a switching tube control signal for enabling the voltage boost circuit 1 to be in a discharge state when the clock signal is at a low level.
Specifically, referring to fig. 4, the output terminal 343 of the operational amplifier circuit 34 is connected to one input terminal a of the PWM signal generation circuit 22. The output terminal of the booster circuit 1 is the cathode 122 of the diode 12 in the booster circuit 1.
Optionally, the period of the clock signal is 1 second, and the duration of the low level in one clock period is 10 microseconds. Specifically, referring to fig. 4, when the voltage boost circuit 1 includes the first switch tube 14, at this time, the logic circuit 21 may include a first and gate 211, two input terminals of the first and gate 211 are respectively connected to the output terminal 311 of the clock circuit 31 and the PWM signal output terminal B of the PWM signal generation circuit 22, and an output terminal of the first and gate 211 is connected to the control terminal of the first switch tube 14.
Referring to fig. 4, the specific operation of the circuit will be described in detail.
Specifically, when the clock signal is at a low level, the sampling circuit 32 is in a sampling state. Thus, the output terminal of the first and gate 211 outputs a low level regardless of whether the PWM signal is a high level or a low level. When the first and gate 211 outputs a low level, the first switch tube 14 is turned off. Further, when the first switching tube 14 is turned off, the photovoltaic power source 4 is in a discharging state. At this time, the voltage on the energy storage element 5 side is higher than the voltage on the photovoltaic power source 4 side, and the diode 12 is turned off. And when the diode 12 is off, the photovoltaic power source 4 is considered to be in an open circuit state. In this way, the sampling circuit 32 can acquire the open-circuit voltage voc of the photovoltaic power source 4.
When the collecting circuit 32 collects the open-circuit voltage voc of the photovoltaic power source 4, and the open-circuit voltage voc is input to the proportional circuit 33, the proportional circuit 33 can proportionally amplify the open-circuit voltage voc, in this embodiment, the open-circuit voltage voc is amplified to 0.8 times. I.e. the output voltage of the proportional circuit 33 is 0.8 voc. Further, the non-inverting input terminal 341 of the operational amplifier circuit 34 is connected to the proportional circuit 33, the inverting input terminal 342 is connected to the photovoltaic power supply 4, and the voltage of the inverting input terminal 342 is equal to the voltage of the non-inverting input terminal 341 according to the virtual short characteristic of the operational amplifier circuit, and at this time, the voltage of the non-inverting input terminal 342 is considered to be equal to 0.8voc, that is, the output voltage of the photovoltaic power supply 4 is 0.8 voc.
Further, when the clock signal is at a high level, the sampling circuit 32 enters a hold state, and at this time, the switching tube control signal output by the switching tube control circuit 2 is completely determined by the PWM signal. At this time, the entire circuit enters a normal operation mode. At this time, the output voltage of the photovoltaic power source 4 is already fixed at 0.8 voc. Thus, referring to fig. 3, the photovoltaic power source 4 can only output a current corresponding to the voltage (0.8voc), and at this time, the photovoltaic power source 4 outputs the maximum power.
Fig. 5 is a schematic diagram of a PWM signal generating circuit in the circuit shown in fig. 4 according to an exemplary embodiment of the present application. Referring to fig. 5, in the example shown in fig. 4, the PWM signal generating circuit 22 may include an error amplifier 221, an I/V conversion circuit 222, a PWM comparator 223, and a logic chip 224, wherein,
the input terminal of the I/V conversion circuit 222 is an input terminal C of the PWM signal generation circuit 22. Referring to the foregoing description, the input terminal of the I/V conversion circuit 222 is connected to the booster circuit 1 (i.e., to the anode 121 of the diode 12 in the booster circuit 1). Further, an output terminal of the I/V conversion circuit 222 is connected to a non-inverting input terminal of the PWM comparator 223;
further, the inverting input terminal of the error amplifier 221 is the other input terminal a of the PWM signal generating circuit 22, which is connected to the output terminal 343 of the operational amplifier circuit 34. In addition, the non-inverting input terminal of the error amplifier 221 is grounded via a reference power supply.
In addition, the output terminal of the PWM comparator 223 is connected to the input terminal of the logic chip 224, and the output terminal of the logic chip 224 is the PWM signal output terminal C of the PWM signal generating circuit 22, which outputs the PWM signal (i.e. the output terminal of the logic chip 224 is connected to one input terminal of the first and gate 211).
Specifically, the specific operation principle of the PWM signal generating circuit can be referred to the description of the related art, and is not described herein again.
Fig. 6 is a schematic diagram of a third embodiment of a photovoltaic power generation charge and discharge control circuit provided in the present application. Fig. 7 is a schematic diagram of a PWM signal generating circuit in the circuit shown in fig. 6 according to an exemplary embodiment of the present application.
Referring to fig. 6 and fig. 7, on the basis of the above embodiments, in the photovoltaic power generation charge and discharge control circuit provided in this embodiment, the PWM signal generation circuit 22 includes an overcurrent protection circuit 225, where the overcurrent protection circuit 225 includes an overcurrent comparator 2251, and a second switching tube 2252 and a third switching tube 2253 respectively connected to non-inverting input terminals of the overcurrent comparator 2251; the second switching tube 2251 is also connected to a first reference power source 6, and the third switching tube 2253 is also connected to a second reference power source 7.
Further, the voltage of the first reference power supply 6 is larger than the voltage of the second reference power supply 7; the first switch tube 2252 is turned on when its control terminal is switched in a high level, and is turned off when its control terminal is switched in a low level; the second switch tube 2253 is turned off when the control terminal thereof is switched to a high level, and turned on when the control terminal thereof is switched to a low level.
The MPPT control circuit further includes an open-circuit voltage comparator 35, wherein a non-inverting input terminal 351 of the open-circuit voltage comparator 35 is connected to the analog signal output terminal 313 of the sampling circuit 31, an inverting input terminal 352 is connected to the third reference power supply 8, and an output terminal 353 is connected to the control terminals D of the first and second switching tubes 2252 and 2253.
Specifically, the second switching tube 2252 and the third switching tube 2253 may be MOS tubes, and this embodiment is not limited thereto.
Referring to fig. 6 and 7, as can be seen from the foregoing description, the sampling circuit 32 outputs the open circuit voltage of the photovoltaic power source 4, and further, the voltage comparator 35 compares the open circuit voltage with the voltage of the third reference power source 8, and further outputs a high level when the open circuit voltage is greater than the voltage of the third reference power source 8. When the open circuit voltage is lower than the voltage of the third reference power supply 8, a low level is output. Thus, when the open circuit voltage is greater than the voltage of the third reference power supply 8, the first signal output from the voltage comparator 35 is at a high level, and at this time, the second switch 2252 is turned on, so that the current comparator 2251 performs overcurrent protection according to the voltage of the first reference power supply 6.
Further, when the open circuit voltage is smaller than the voltage of the third reference power supply 8, the first signal output by the voltage comparator 35 is at a low level, at this time, the third switching tube 2253 is turned on, and the current comparator 2251 performs overcurrent protection according to the voltage of the second reference power supply 7. And the voltage value of the first reference power supply 6 is larger than the voltage value of the second reference power supply 7. Therefore, when the open-circuit voltage is larger, the overcurrent protection can be carried out according to the larger reference voltage, and when the open-circuit voltage is smaller, the smaller reference voltage is selected for overcurrent protection, so that the reference voltage according to the overcurrent protection is matched with the open-circuit.
Further, referring to fig. 8, fig. 8 is a graph illustrating a luminance characteristic of a photovoltaic power source according to an exemplary embodiment of the present application. Referring to fig. 8, the lower the ambient brightness, the smaller the open circuit voltage of the photovoltaic power source, and the lower the ambient brightness, the smaller the short circuit current. With the above description, the reference voltage based on the overcurrent protection is matched with the open circuit, that is, the reference voltage based on the overcurrent protection is matched with the ambient brightness, so as to prevent the current limiting protection function from being disabled due to the overlarge reference voltage when the brightness is low (at this time, the short-circuit current is small), or to prevent the current output capability from being limited due to the undersize reference voltage when the brightness is high.
Further, with reference to fig. 6, in the photovoltaic power generation charge and discharge control circuit provided in this embodiment, the boost circuit 1 further includes a fourth switching tube 15; the logic circuit 21 further comprises a second and gate 212; two input ends of the second and gate 212 are respectively connected to the output end of the first and gate 211 and the output end 353 of the open-circuit voltage comparator 35, and the output end of the second and gate 212 is connected to the control end of the fourth switching tube 15.
Specifically, referring to fig. 6 and the operation principle of the circuit diagram shown in fig. 4 described above, the operation principle of the circuit diagram shown in fig. 6 will be briefly described.
Specifically, when the clock signal is at a low level, no matter whether the first signal output from the voltage comparator 35 is at a high level or at a low level, the output from the first and gate 211 is at a low level, and the output from the second and gate 212 is also at a low level. When the output of the second and gate 212 is at a low level, the fourth switching tube 15 is also in a cut-off state, so that the open-circuit voltage of the photovoltaic power source 4 can be collected.
Further, when the clock signal is high and the whole circuit enters the normal operation mode, the output of the first and gate 211 is completely controlled by the PWM signal. Further, when the open circuit voltage is greater than the voltage of the third reference power supply 8, the first signal output by the voltage comparator 35 is at a high level, and at this time, the output of the second and gate 212 is completely controlled by the PWM signal. That is, both the first switching tube 14 and the fourth switching tube 15 perform a switching operation. When the open circuit voltage is lower than the voltage of the third reference power supply 8, the first signal output by the voltage comparator 35 is at a low level, and the second and gate 212 outputs a low level. When the output of the second and gate 212 is at low level, the fourth switch tube 15 is turned off. At this time, only the first switching tube 14 performs the switching operation.
In order to improve the efficiency of the booster circuit, it is desirable that the area of the switching tube of the booster circuit is as small as possible under low load conditions, and that the on-resistance of the switching tube of the booster circuit is as small as possible under high load conditions, and that the on-resistance of the switching tube is inversely proportional to the area thereof, that is, that the area of the switching tube in the booster circuit is as large as possible under high load conditions. In this way, referring to the foregoing description, by providing the first switching tube and the fourth switching tube in the voltage boost circuit, when the current ambient brightness is low (i.e., when the open-circuit voltage is low), only the first switching tube is enabled to perform the switching operation, and when the current ambient brightness is high, the first switching tube and the fourth switching tube are enabled to perform the switching operation, so that the area of the switching tube in the voltage boost circuit is matched with the current load, and the efficiency of the voltage boost circuit is improved.
Optionally, referring to fig. 6, the photovoltaic power generation charging and discharging circuit further includes a voltage divider 9, the voltage divider 9 is disposed between the MPPT control circuit 3 and the error amplifier 221 of the PWM signal generator 22, and the voltage divider 9 and the error amplifier 221 form a phase compensation circuit for the MPPT control circuit.
Referring to fig. 6, the voltage dividing circuit 9 includes a first resistor R1, a second resistor R2, and a third resistor R3; wherein the content of the first and second substances,
the output terminal 343 of the amplifier operator circuit is connected to the output terminal of the voltage boost circuit 1 (i.e. the cathode 122 of the diode 12 in the voltage boost circuit 1) through a first resistor R1 and a second resistor R2, the output terminal 343 of the amplifier operator circuit 34 is connected to the inverting input terminal of the error amplifier 221 through a first resistor R1, one end of the first resistor R1 connected to the second resistor R2 is connected to the first end of the third resistor R3, and the second end of the third resistor R3 is grounded.
Specifically, the voltage divider 9 and the error amplifier 221 constitute the phase compensation circuit for MPPT control circuit. The voltage at the non-inverting input of the error amplifier is now equal to the voltage at the inverting input, so that the voltage at the cathode 122 of the diode 12 is now stabilized by the voltage dividing action of the resistors and the regulating action of the operational amplifier circuit 34.
The above description is only exemplary of the present application and should not be taken as limiting the present application, as any modification, equivalent replacement, or improvement made within the spirit and principle of the present application should be included in the scope of protection of the present application.
Claims (2)
1. A photovoltaic power generation charge-discharge control circuit is characterized by comprising a booster circuit, a switching tube control circuit and a Maximum Power Point Tracking (MPPT) control circuit; wherein the content of the first and second substances,
the switch tube control circuit is connected with the booster circuit and is used for controlling the charge and discharge state of the booster circuit;
the MPPT control circuit is respectively connected with a photovoltaic power supply, the booster circuit and the switching tube control circuit, and is used for collecting the open-circuit voltage of the photovoltaic power supply when the booster circuit is in a discharge state, and adjusting the output voltage of the photovoltaic power supply according to the open-circuit voltage so as to enable the photovoltaic power supply to output at the maximum power;
the switching tube control circuit comprises a logic circuit and a Pulse Width Modulation (PWM) signal generation circuit, wherein,
the input end of the logic circuit is respectively connected with the MPPT control circuit and the PWM signal generating circuit, and the output end of the logic circuit is connected with the control end of the booster circuit and used for generating a switch tube control signal for controlling the charging and discharging state of the booster circuit according to the signal from the MPPT control circuit and the PWM signal from the PWM signal generating circuit;
the PWM signal generating circuit is also connected with the MPPT control circuit and the booster circuit and is used for generating a PWM signal according to the output voltage of the MPPT control circuit and the voltage corresponding to the output current of the booster circuit;
the MPPT control circuit comprises a clock circuit, a sampling circuit, a proportional circuit and an operational amplifier circuit, wherein,
the output end of the clock circuit is respectively connected with the control signal input ends of the logic circuit and the sampling circuit;
the analog signal input end of the sampling circuit is connected with the photovoltaic power supply, and the analog signal output end of the sampling circuit is connected with the input end of the proportional circuit; the sampling circuit is used for working in a sampling state when a clock signal generated by the clock circuit is at a low level and working in a holding state when the clock signal generated by the clock circuit is at a high level;
the output end of the proportional circuit is connected with the non-inverting input end of the operational amplifier circuit, the inverting input end of the operational amplifier circuit is connected with the photovoltaic power supply, and the output end of the operational amplifier circuit is respectively connected with the output end of the booster circuit and the PWM signal generating circuit;
the switching tube control circuit is used for generating a switching tube control signal for enabling the boosting circuit to be in a discharging state when the clock signal is at a low level;
the photovoltaic power generation charging and discharging circuit further comprises a voltage division circuit, the voltage division circuit is arranged between the MPPT control circuit and an error amplifier of the PWM signal generating circuit, and the voltage division circuit and the error amplifier form a phase compensation circuit for the MPPT control circuit;
the voltage division circuit comprises a first resistor, a second resistor and a third resistor; wherein the content of the first and second substances,
the output end of the operational amplifier circuit is connected with the output end of the booster circuit through a first resistor and a second resistor, the output end of the operational amplifier circuit is connected with the inverting input end of the error amplifier through a first resistor, one end of the first resistor, which is connected with the second resistor, is connected with the first end of a third resistor, and the second end of the third resistor is grounded;
the boost circuit comprises a first switch tube, the logic circuit comprises a first AND gate, two input ends of the first AND gate are respectively connected with the output end of the clock signal and the PWM signal output end of the PWM signal generating circuit, and the output end of the first AND gate is connected with the control end of the first switch tube;
the PWM signal generating circuit comprises an overcurrent protection circuit, and the overcurrent protection circuit comprises an overcurrent comparator, and a second switching tube and a third switching tube which are respectively connected with the non-inverting input end of the overcurrent comparator; the second switch tube is also connected with a first reference power supply, the third switch tube is also connected with a second reference power supply, wherein,
the voltage of the first reference power supply is greater than the voltage of the second reference power supply; the first switch tube is switched on when the control end of the first switch tube is connected with a high level, and is switched off when the control end of the first switch tube is connected with a low level; the second switch tube is cut off when the control end of the second switch tube is connected with a high level, and is switched on when the control end of the second switch tube is connected with a low level;
the MPPT control circuit further comprises an open-circuit voltage comparator, wherein the in-phase input end of the open-circuit voltage comparator is connected with the analog signal output end of the sampling circuit, the reverse-phase input end of the open-circuit voltage comparator is connected with a third reference power supply, and the output end of the open-circuit voltage comparator is connected with the control end of the first switch tube and the control end of the second switch tube respectively.
2. The circuit of claim 1, wherein the boost circuit further comprises a fourth switching tube; the logic circuit further comprises a second AND gate; the two input ends of the second AND gate are respectively connected with the output end of the first AND gate and the output end of the open-circuit voltage comparator, and the output end of the second AND gate is connected with the control end of the fourth switching tube.
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| CN113452074B (en) * | 2021-06-29 | 2024-04-09 | 华为数字能源技术有限公司 | Photovoltaic system and control method |
| US11862981B2 (en) | 2020-06-18 | 2024-01-02 | Huawei Digital Power Technologies Co., Ltd. | Photovoltaic system and control method |
| CN111864840B (en) * | 2020-07-22 | 2021-12-07 | 重庆英卡电子有限公司 | Solar charging controller with load control function |
| CN113364082A (en) * | 2021-05-26 | 2021-09-07 | 国网江西省电力有限公司供电服务管理中心 | Efficient MPPT control system for cooperative collection of multiple micro-energies |
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| TWI331264B (en) * | 2006-12-26 | 2010-10-01 | Richtek Technology Corp | Analog photovoltaic power circuit |
| CN201758372U (en) * | 2010-06-30 | 2011-03-09 | 田方共 | Solar energy power source with power converter |
| CN103440019A (en) * | 2013-08-20 | 2013-12-11 | 江苏大学 | Analogy control circuit capable of achieving photovoltaic cell maximum power point tracing |
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