MPPT charging and discharging circuit

Abstract

The invention belongs to the technical field of inverters, and discloses an MPPT charging and discharging circuit which comprises an inductor L1, one end of the inductor L1 is connected with the positive end of a power supply PV, the other end of the inductor L1 is connected with a pin 2 of a switching tube Q1 and a pin 3 of a switching tube Q2, the pin 3 of the switching tube Q1 is connected with one end and the positive output end of a capacitor C1, and the other end of the capacitor C1 is connected with the positive output end of the capacitor C1. A pin 2 of the switch tube Q2 is connected with a pin 3 of the switch tube Q3 and one end of an inductor L2, the other end of the capacitor C1 and the other end of the inductor L2 are connected with the positive end of a battery BAT and the negative end of a power supply PV, the pin 2 of the switch tube Q3 and the negative end of the battery BAT are connected with an output negative end, and the output positive end and the output negative end are connected with an inverter circuit. The beneficial effects of the invention are that the circuit structure is simple, the operation is stable, and all working modes in the optical storage inverter can be realized.

Description

Technical Field

[0001] The present invention relates to the technical field of inverters, and in particular to an MPPT charging and discharging circuit. Background Art

[0002] An inverter is a power regulation device composed of semiconductor devices, which is mainly used to convert DC power into AC power. It is generally composed of a boost circuit and an inverter bridge circuit. The boost circuit boosts the DC voltage of the solar cell to the DC voltage required for the inverter output control, and the inverter bridge circuit converts the boosted DC voltage into an AC voltage of a common frequency. There are many types of inverters, so special attention should be paid when selecting the model and capacity, especially in solar power generation systems, where the efficiency of the inverter is an important factor in determining the capacity of the solar cell and the battery.

[0003] The Maximum Power Point Tracking (MPPT) system is an electrical system that adjusts the working state of the electrical module to enable the photovoltaic panel to output more electrical energy. It can effectively store the direct current generated by the solar panel in the battery, and can effectively solve the living and industrial electricity consumption in remote areas and tourist areas that are not covered by conventional power grids without causing environmental pollution.

[0004] Therefore, it is necessary to provide an MPPT charging and discharging circuit with a simple circuit structure and stable operation, which can realize all working modes in the photovoltaic storage inverter. Summary of the invention

[0005] The invention discloses an MPPT charging and discharging circuit, which can effectively solve the technical problems involved in the background technology.

[0006] To achieve the above object, the technical solution of the present invention is:

[0007] An MPPT charging and discharging circuit includes an inductor L1, one end of the inductor L1 is connected to the positive end of a power source PV, the other end of the inductor L1 is connected to pin 2 of a switch tube Q1 and pin 3 of a switch tube Q2, pin 3 of the switch tube Q1 is connected to one end of a capacitor C1 and an output positive end, pin 2 of the switch tube Q2 is connected to pin 3 of a switch tube Q3 and one end of the inductor L2, the other end of the capacitor C1 and the other end of the inductor L2 are connected to the positive end of a battery BAT, and the negative end of the power source PV, pin 2 of the switch tube Q3, and the negative end of the battery BAT are connected to the output negative end.

[0008] As a preferred improvement of the present invention: the power source PV is a solar panel.

[0009] As a preferred improvement of the present invention: the power source PV is a direct current power source.

[0010] As a preferred improvement of the present invention: the output positive terminal and the output negative terminal are connected to an inverter circuit.

[0011] As a preferred improvement of the present invention: the switch tube Q1, the switch tube Q2 and the switch tube Q3 are MOS tubes or IGBT tubes.

[0012] As a preferred improvement of the present invention: pins 1 of the switch tube Q1 , the switch tube Q2 , and the switch tube Q3 are all connected to the MCU.

[0013] As a preferred improvement of the present invention: the capacitor C1 is an electrolytic capacitor.

[0014] The beneficial effects of the present invention are as follows:

[0015] The circuit structure is simple and the cost is low. An MPPT circuit can be formed by two inductors, one capacitor and three switching tubes, which are respectively connected to the power supply, battery and inverter circuit. This structure can realize all working modes in the photovoltaic storage inverter, including the battery charging and discharging process and the process of outputting current to the inverter circuit. The circuit structure is stable and efficient, which can fully improve the working efficiency of the inverter. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work, among which:

[0017] Figure 1 It is a schematic diagram of an MPPT charging and discharging circuit of the present invention.

[0018] In the figure: 101- output positive terminal, 102- output negative terminal. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the present invention will be described clearly and completely below in combination with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0021] In addition, in the present invention, descriptions such as "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0022] In the present invention, unless otherwise clearly specified and limited, the terms "connection", "fixation", etc. should be understood in a broad sense. For example, "fixation" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0023] In addition, the technical solutions between the various embodiments of the present invention can be combined with each other, but it must be based on the fact that ordinary technicians in the field can implement it. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0024] See also Figure 1 As shown, the present invention provides an MPPT charging and discharging circuit, including an inductor L1, one end of the inductor L1 is connected to the positive end of the power supply PV, the other end of the inductor L1 is connected to the pin 2 of the switch tube Q1 and the pin 3 of the switch tube Q2, the pin 3 of the switch tube Q1 is connected to one end of the capacitor C1 and the output positive terminal 101, the pin 2 of the switch tube Q2 is connected to the pin 3 of the switch tube Q3 and one end of the inductor L2, the other end of the capacitor C1 and the other end of the inductor L2 are connected to the positive end of the battery BAT, the negative end of the power supply PV, the pin 2 of the switch tube Q3 and the negative end of the battery BAT are connected to the output negative terminal 102, the output positive terminal 101 and the output negative terminal 102 are connected to the inverter circuit, the pins 1 of the switch tubes Q1, Q2 and Q3 are all connected to the MCU, and the power supply PV is a DC power supply. In this embodiment, the switch tube adopts a triode, and each pin is defined as follows: pin 1 is the base, pin 2 is the emitter, and pin 3 is the collector.

[0025] Specifically, the power source PV provides current, which can charge the battery BAT through the operation of the inductor and the switch tube, and can also supply power to the load connected between the output positive terminal 101 and the output negative terminal 102. The battery BAT can also supply power to the load connected between the output positive terminal 101 and the output negative terminal 102. The inverter circuit receives the direct current provided by the MPPT charging and discharging circuit, converts it into alternating current, and then supplies it to other electrical appliances. The inverter circuit is a common circuit in the inverter.

[0026] As an implementation mode, the power source PV is a solar panel, which uses solar energy to generate electricity, and after conversion, it supplies power to household appliances. The switch tube Q1, the switch tube Q2 and the switch tube Q3 are MOS tubes or IGBT tubes, and each pin of the switch tube can be defined as pin 1 gate, pin 2 source, and pin 3 drain. The capacitor C1 is an electrolytic capacitor, the positive electrode of the capacitor C1 is connected to the output positive terminal 101, and the negative electrode of the capacitor C1 is connected to the battery BAT. It should be further explained that the use of other components to achieve the above-mentioned effects should all belong to the inventive concept of the present invention and should belong to the protection scope of the present invention.

[0027] Working principle:

[0028] 1. The switch tube Q2 is in PWM state, enabling the power supply PV to charge the battery BAT.

[0029] 2. The power supply PV and the battery BAT discharge together, and the switch tube Q2 and the switch tube Q3 work at the same time; when the switch tube Q2 and the switch tube Q3 are turned on at the same time, the inductor L1 and the inductor L2 are charged; when the switch tube Q2 and the switch tube Q3 are turned off at the same time, the inductor L1 and the inductor L2 discharge to the capacitor C1; when the switch tube Q2 is turned on and the switch tube Q3 is turned off, the power supply PV charges the battery BAT; when the switch tube Q2 is turned off and the switch tube Q3 is turned on, the battery BAT discharges to the inverter circuit bus.

[0030] 3. The switch tubes Q1 and Q2 are turned on, and the capacitor C1 charges the battery BAT.

[0031] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and the embodiments. They can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to the specific details and the illustrations shown and described herein.

Claims

1. A MPPT charging and discharging circuit, Features: The invention comprises an inductor L1, one end of which is connected to the positive end of a power source PV, the other end of which is connected to the pin 2 of a switch tube Q1 and the pin 3 of a switch tube Q2, the pin 3 of the switch tube Q1 is connected to one end of a capacitor C1 and an output positive end (101), the pin 2 of the switch tube Q2 is connected to the pin 3 of the switch tube Q3 and one end of the inductor L2, the other end of the capacitor C1 and the other end of the inductor L2 are connected to the positive end of a battery BAT, and the negative end of the power source PV, the pin 2 of the switch tube Q3 and the negative end of the battery BAT are connected to the output negative end (102).

2. A MPPT charging and discharging circuit according to claim 1, Features: The power source PV is a solar panel.

3. The MPPT charging and discharging circuit according to claim 1, Features: The power source PV is a direct current power source.

4. The MPPT charging and discharging circuit according to claim 1, Features: The output positive terminal (101) and the output negative terminal (102) are connected to an inverter circuit.

5. The MPPT charging and discharging circuit according to claim 1, Features: The switch tube Q1, the switch tube Q2 and the switch tube Q3 are MOS tubes or IGBT tubes.

6. The MPPT charging and discharging circuit according to claim 1, Features: Pins 1 of the switch tube Q1 , the switch tube Q2 , and the switch tube Q3 are all connected to the MCU.

7. The MPPT charging and discharging circuit according to claim 1, Features: The capacitor C1 is an electrolytic capacitor.

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