Photovoltaic inverter parallel operation current sharing control circuit

Abstract

The utility model belongs to the technical field of photovoltaic inverters, and particularly discloses a photovoltaic inverter parallel operation current sharing control circuit, which comprises a synchronous signal generation module, a current sharing module and a current sharing module, the current-sharing control module is used for realizing balanced distribution of current; the voltage regulation module is used for realizing current sharing control; the current detection module is used for detecting the output current of the photovoltaic inverter; a communication module; according to the utility model, the current detection module transmits detected output current signals of each inverter to the voltage regulation module and the current-sharing control module, and the voltage regulation module regulates the output voltage of the photovoltaic inverter according to a control instruction generated by the current-sharing control module. The power equalization and voltage stabilization among the photovoltaic inverters are realized, and the ring current and power loss are reduced, so that the accurate control of the parallel operation of the photovoltaic inverters is realized, and the stability and efficiency of the system are improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to photovoltaic inverter technical field, concretely is a photovoltaic inverter parallel machine current -sharing control circuit. BACKGROUND

[0002] Photovoltaic inverter parallel machine control is to ensure that multiple inverters can work cooperatively, realize the effect of stable and efficient electric energy conversion, the current photovoltaic inverter parallel machine control mode is through a central controller to unify management and coordination the work of each inverter, including centralized control to the start, stop, power regulation of inverter.

[0003] However, if the centralized control central controller fails, the entire inverter system will fail, the reliability is not high, in addition, in centralized control, the difference of single inverter output current is considered to be caused by the amplitude difference of inverter output voltage, and the circulating current caused by the phase difference of inverter output voltage is not considered, so that the current sharing effect cannot be realized, therefore we need to propose a photovoltaic inverter parallel machine current -sharing control circuit to solve the above problems, so that it can realize accurate control to photovoltaic inverter parallel operation, improve the stability and efficiency of the system. UTILITY MODEL CONTENT

[0004] The utility model aims at providing a photovoltaic inverter parallel machine current -sharing control circuit, can realize accurate control to photovoltaic inverter parallel operation, improve the stability and efficiency of the system, to solve the problem in the background art.

[0005] In order to realize the above-mentioned purpose, the utility model provides the following technical scheme: a photovoltaic inverter parallel machine current -sharing control circuit, comprising: synchronous signal generation module responsible for generating synchronous signal, the synchronous signal generation module connects multiple photovoltaic inverters;

[0006] Current sharing control module for realizing current equalization distribution, the current sharing control module is electrically connected with multiple photovoltaic inverters;

[0007] Voltage regulation module for realizing current sharing control, the voltage regulation module adjusts the output voltage amplitude and phase of photovoltaic inverter according to the instruction of current sharing control module, the voltage regulation module is electrically connected with synchronous signal generation module;

[0008] Current detection module for detecting photovoltaic inverter output current, the current detection module is electrically connected with current sharing control module and synchronous signal generation module;

[0009] Communication module, the communication module is electrically connected with synchronous signal generation module, current sharing control module, voltage regulation module and current detection module respectively.

[0010] Preferably, the synchronization signal generation module includes an arithmetic unit U1 and an arithmetic unit U2. A resistor R4 is connected to the positive terminal of the arithmetic unit U1. One end of the resistor R4 is connected to a resistor R3. One end of the resistor R3 is connected to a capacitor C1. One end of the capacitor C1 is connected to a resistor R1 for connection to a current sharing control module. A resistor R2 for connection to one of the photovoltaic inverters is connected to the connection point of the capacitor C1 and the resistor R1. The connection point of the resistor R3 and the resistor R4 is connected to the negative terminal of the arithmetic unit U1 via a capacitor C2. A capacitor C3 is connected to the positive terminal of the arithmetic unit U1 and the connection terminal of the resistor R4 for connection to another photovoltaic inverter. The other end of the capacitor C3 is connected to the negative terminal of the arithmetic unit U2 through the resistor R6. The output terminal of the arithmetic unit U1 is connected to the positive terminal of the arithmetic unit U2 through the capacitor C4. An adjustable resistor R7 is connected between the negative terminal and the output terminal of the arithmetic unit U2. A capacitor C5 is connected to the output terminal of the arithmetic unit U2 for connection to the remaining photovoltaic inverter. A resistor R5 is connected to the connection terminal of the arithmetic unit U2 and the capacitor C4 for grounding.

[0011] Preferably, the current sharing control module includes a control unit and current sharing adjustment units matched with multiple photovoltaic inverters. The multiple current sharing adjustment units are electrically connected to the control unit, and an inductor L1 is connected between two adjacent current sharing adjustment units. The control unit includes a microcontroller U13.

[0012] Preferably, the current sharing adjustment unit includes an arithmetic unit U3 connected to the photovoltaic inverter. A filter capacitor C6 is connected between the positive and negative terminals of the arithmetic unit U3. The negative terminal of the arithmetic unit U3 is connected to the photovoltaic inverter through a resistor R8. An arithmetic unit U6 is connected to the output terminal of the arithmetic unit U3. A diode D1 is connected to the output terminal of the arithmetic unit U6. One end of the diode D1 is connected to an arithmetic unit U9. The output terminal of the arithmetic unit U9 is connected to a microcontroller U13 through a diode D4. A filter capacitor C9 is connected between the output terminal and the negative terminal of the arithmetic unit U9. The negative terminal of the arithmetic unit U9 is connected to the positive terminal of the arithmetic unit U6.

[0013] Preferably, the voltage regulation module includes a voltage regulator chip U4B. A capacitor C13 is connected between pins 1 and 2 of the voltage regulator chip U4B. A resistor R17, a resistor R13, and a switch S1 are connected in series on pin 2 of the voltage regulator chip U4B. One end of the switch S1 is connected to a resistor R11 for connection with the current sharing control module. A resistor R12 and a capacitor C12 are connected in parallel at the connection point between the switch S1 and the resistor R11. Pins 5 and 7 of the voltage regulator chip U4B are connected. Pin 7 of the voltage regulator chip U4B is connected to the microcontroller U13. A resistor R21 is connected between pins 3 and 16 of the voltage regulator chip U4B. A capacitor C15 is connected at the connection point between pin 3 of the voltage regulator chip U4B and the resistor R21. A capacitor C14 is connected at the connection point between pin 16 of the voltage regulator chip U4B and the resistor R21.

[0014] Preferably, the current detection module includes a current sensing chip U16, with a capacitor C23 and a resistor R23 connected in parallel between pins 3 and 4 of the current sensing chip U16, a capacitor C22 connected to ground connected to pin 6 of the current sensing chip U16, and a resistor R22 connected between pins 1 and 2 of the current sensing chip U16.

[0015] Preferably, the communication module includes a communication chip U25. A transistor Q13 is connected to pin 3 of the communication chip U25. A resistor R98 for connecting to a 5V voltage is connected to the collector of the transistor Q13 and the connection terminal of the communication chip U25. A resistor R99 for connecting to a serial communication interface is connected to the base of the transistor Q13. A capacitor C50 is connected to pin 8 of the communication chip U25. One end of the capacitor C50 is connected to pin 7 of the communication chip U25 through a resistor R157. A connection terminal U43 is connected to the connection terminal of the communication chip U25 through a resistor R84. Pin 2 of the connection terminal U43 is connected to pin 6 of the communication chip U25 through a resistor R85. A resistor R158 for connecting to a 5V voltage is connected to the connection terminal of the communication chip U25 and the connection terminal of the resistor R85.

[0016] Compared with the prior art, the beneficial effects of this utility model are:

[0017] 1. This utility model utilizes the cooperation of a synchronization signal generation module, a current sharing control module, a voltage regulation module, and a current detection module. The current detection module transmits the detected output current signals of each inverter to the voltage regulation module and the current sharing control module. The voltage regulation module adjusts the output voltage of the photovoltaic inverters according to the control commands generated by the current sharing control module, thereby achieving power sharing and voltage stability among the photovoltaic inverters, reducing circulating current and power loss, and thus realizing precise control of the parallel operation of photovoltaic inverters, improving the stability and efficiency of the system.

[0018] 2. The communication module of this utility model can ensure timely and accurate transmission of information between the synchronization signal generation module, the current sharing control module, the voltage regulation module and the current detection module, so as to realize the coordinated control and optimization of the parallel system and improve the reliability and stability of the system. Attached Figure Description

[0019] Figure 1 This is a system diagram of the present invention;

[0020] Figure 2 This is the circuit diagram of the synchronization signal generation module of this utility model;

[0021] Figure 3 This is the circuit diagram of the current sharing control module of this utility model;

[0022] Figure 4 This is the circuit diagram of the voltage regulation module of this utility model;

[0023] Figure 5 This is the circuit diagram of the current detection module of this utility model;

[0024] Figure 6 This is a circuit diagram of the communication module of this utility model. Detailed Implementation

[0025] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0026] Please see Figures 1-6 This utility model provides a technical solution: a photovoltaic inverter parallel current sharing control circuit, including: a synchronization signal generation module responsible for generating synchronization signals, wherein the synchronization signal generation module is connected to multiple photovoltaic inverters;

[0027] The synchronization signal generation module includes an arithmetic unit U1 and an arithmetic unit U2. A resistor R4 is connected to the positive terminal of the arithmetic unit U1. A resistor R3 is connected to one end of resistor R4. A capacitor C1 is connected to one end of resistor R3. A resistor R1 is connected to one end of capacitor C1 for connection to the current sharing control module. A resistor R2 is connected to the connection point between capacitor C1 and resistor R1 for connection to one of the photovoltaic inverters. The connection point between resistor R3 and resistor R4 is connected to the negative terminal of the arithmetic unit U1 via capacitor C2. A capacitor is connected to the positive terminal of the arithmetic unit U1 for connection to the other photovoltaic inverter. C3, the other end of which is connected to the negative terminal of the arithmetic unit U2 via resistor R6. The output terminal of the arithmetic unit U1 is connected to the positive terminal of the arithmetic unit U2 via capacitor C4. An adjustable resistor R7 is connected between the negative terminal and the output terminal of the arithmetic unit U2. A capacitor C5 is connected to the output terminal of the arithmetic unit U2 for connecting to the remaining photovoltaic inverter. A resistor R5 for grounding is connected to the connection terminal of the arithmetic unit U2 and capacitor C4. The arithmetic units U1 and U2 are used to meet the requirements of fast and accurate phase synchronization. By adjusting the adjustable resistor R7, the output of the arithmetic unit U2 can be finely adjusted, thereby achieving fine adjustment of phase synchronization.

[0028] A current sharing control module for achieving balanced current distribution, the current sharing control module being electrically connected to multiple photovoltaic inverters;

[0029] The current sharing control module includes a control unit and current sharing adjustment units matched with multiple photovoltaic inverters. Each current sharing adjustment unit is electrically connected to the control unit, and an inductor L1 is connected between adjacent current sharing adjustment units. Figure 3 (L1 and L2 are the same, the only difference is the installation location), and the control unit includes a microcontroller U13.

[0030] like Figure 3As shown, the current sharing adjustment unit has three groups. The first group consists of resistor R8, capacitor C6, arithmetic unit U3, arithmetic unit U6, diode D1, diode D4, and arithmetic unit U9. The second group consists of resistor R9, capacitor C7, arithmetic unit U4, arithmetic unit U7, diode D2, diode D5, and arithmetic unit U11. The third group consists of resistor R10, capacitor C8, arithmetic unit U5, arithmetic unit U8, diode D3, diode D6, and arithmetic unit U12. Taking the first group as an example, the current sharing adjustment unit includes arithmetic unit U3 connected to the photovoltaic inverter. A filter capacitor C6 is connected between the positive and negative terminals of arithmetic unit U3. The negative terminal of arithmetic unit U3 is connected to the photovoltaic inverter through resistor R8. The output terminal of arithmetic unit U3... An arithmetic logic unit (ALU) U6 is connected to a diode D1 at its output. One end of diode D1 is connected to an ALU U9. The output of ALU U9 is connected to a microcontroller U13 via diode D4. A filter capacitor C9 is connected between the output of ALU U9 and its negative terminal. The negative terminal of ALU U9 is connected to the positive terminal of ALU U6. ALU U3, ALU U6, and ALU U9 are used to process current data and execute control algorithms. Filter capacitors C9 and C6 are used to filter out high-frequency noise and interference. Diodes D1 and D4 are used to protect the circuit from reverse voltage and current surges. Simultaneously, they enable unidirectional signal transmission, ensuring the accuracy of the control signal.

[0031] A voltage regulation module for implementing current sharing control, wherein the voltage regulation module adjusts the output voltage amplitude and phase of the photovoltaic inverter according to the instructions of the current sharing control module, and the voltage regulation module is electrically connected to the synchronization signal generation module;

[0032] The voltage regulation module includes a voltage regulator chip U4B. A capacitor C13 is connected between pins 1 and 2 of the voltage regulator chip U4B. A resistor R17, a resistor R13, and a switch S1 are connected in series on pin 2 of the voltage regulator chip U4B. One end of the switch S1 is connected to a resistor R11 for connection to the current sharing control module. A resistor R12 and a capacitor C12 are connected in parallel on the connection end of the switch S1 and the resistor R11. Pins 5 and 7 of the voltage regulator chip U4B are connected. Pin 7 of the voltage regulator chip U4B is connected to the microcontroller U13. A resistor R21 is connected between pins 3 and 16 of the voltage regulator chip U4B, and a capacitor C15 is connected to the connection between pin 3 of the voltage regulator chip U4B and the resistor R21. A capacitor C14 is connected to the connection between pin 16 of the voltage regulator chip U4B and the resistor R21. During the system debugging phase, the parameters of the voltage regulator chip U4B, resistors, capacitors, and other components are calibrated to ensure the accuracy and stability of the circuit. By debugging and optimizing the microcontroller U13, it is ensured that it can respond quickly and accurately to the instructions of the current sharing control module.

[0033] A current detection module for detecting the output current of a photovoltaic inverter, wherein the current detection module is electrically connected to a current sharing control module and a synchronization signal generation module;

[0034] The current detection module includes a current sensing chip U16. A capacitor C23 and a resistor R23 are connected in parallel between pins 3 and 4 of the current sensing chip U16. A capacitor C22 is connected to ground at pin 6 of the current sensing chip U16. A resistor R22 is connected between pins 1 and 2 of the current sensing chip U16. The current sensing chip U16 accurately detects the output current of each inverter module in real time, providing crucial data for current sharing control.

[0035] The communication module is electrically connected to the synchronization signal generation module, the current sharing control module, the voltage regulation module, and the current detection module, respectively.

[0036] The communication module includes a communication chip U25. A transistor Q13 is connected to pin 3 of the communication chip U25. A resistor R98 for connecting to a 5V voltage is connected to the collector of transistor Q13 and the connection terminal of the communication chip U25. A resistor R99 for connecting to a serial communication interface is connected to the base of transistor Q13. A capacitor C50 is connected to pin 8 of the communication chip U25. One end of capacitor C50 is connected to pin 7 of the communication chip U25 through a resistor R157. A connection terminal U43 is connected to the connection terminal of the communication chip U25 through a resistor R84. Pin 2 of the connection terminal U43 is connected to pin 6 of the communication chip U25 through a resistor R85. A resistor R158 for connecting to a 5V voltage is connected to the connection terminal of the communication chip U25 and the connection terminal of the resistor R85. The communication chip U25 ensures smooth communication between modules, enabling precise control of the parallel operation of the inverters and improving system stability and efficiency.

[0037] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A photovoltaic inverter parallel current sharing control circuit, characterized in that: include: A synchronization signal generating module is responsible for generating synchronization signals, and the synchronization signal generating module is connected to multiple photovoltaic inverters; A current sharing control module for achieving balanced current distribution, the current sharing control module being electrically connected to multiple photovoltaic inverters; The current sharing control module includes a control unit and a current sharing adjustment unit matched with multiple photovoltaic inverters. The multiple current sharing adjustment units are electrically connected to the control unit. An inductor L1 is connected between two adjacent current sharing adjustment units. The control unit includes a microcontroller U13. The current sharing adjustment unit includes an arithmetic unit U3 connected to the photovoltaic inverter. A filter capacitor C6 is connected between the positive and negative terminals of the arithmetic unit U3. The negative terminal of the arithmetic unit U3 is connected to the photovoltaic inverter through a resistor R8. An arithmetic unit U6 is connected to the output terminal of the arithmetic unit U3. A diode D1 is connected to the output terminal of the arithmetic unit U6. One end of the diode D1 is connected to an arithmetic unit U9. The output terminal of the arithmetic unit U9 is connected to a microcontroller U13 through a diode D4. A filter capacitor C9 is connected between the output terminal and the negative terminal of the arithmetic unit U9. The negative terminal of the arithmetic unit U9 is connected to the positive terminal of the arithmetic unit U6. A voltage regulation module for implementing current sharing control, wherein the voltage regulation module adjusts the output voltage amplitude and phase of the photovoltaic inverter according to the instructions of the current sharing control module, and the voltage regulation module is electrically connected to the synchronization signal generation module; A current detection module for detecting the output current of a photovoltaic inverter, wherein the current detection module is electrically connected to a current sharing control module and a synchronization signal generation module; The communication module is electrically connected to the synchronization signal generation module, the current sharing control module, the voltage regulation module, and the current detection module, respectively.

2. The photovoltaic inverter parallel current sharing control circuit according to claim 1, characterized in that: The synchronization signal generation module includes an arithmetic unit U1 and an arithmetic unit U2. A resistor R4 is connected to the positive terminal of the arithmetic unit U1. One end of resistor R4 is connected to a resistor R3. One end of resistor R3 is connected to a capacitor C1. One end of capacitor C1 is connected to a resistor R1 for connection to the current sharing control module. A resistor R2 for connection to one of the photovoltaic inverters is connected to the connection point of capacitor C1 and resistor R1. The connection point of resistor R3 and resistor R4 is connected to the negative terminal of the arithmetic unit U1 via capacitor C2. A capacitor C3 is connected to the positive terminal of the photovoltaic inverter and the resistor R4. The other end of the capacitor C3 is connected to the negative terminal of the arithmetic unit U2 through the resistor R6. The output terminal of the arithmetic unit U1 is connected to the positive terminal of the arithmetic unit U2 through the capacitor C4. An adjustable resistor R7 is connected between the negative terminal and the output terminal of the arithmetic unit U2. A capacitor C5 is connected to the output terminal of the arithmetic unit U2 for connecting to the remaining photovoltaic inverter. A resistor R5 is connected to the connection terminal of the arithmetic unit U2 and the capacitor C4 for grounding.

3. The photovoltaic inverter parallel current sharing control circuit according to claim 1, characterized in that: The voltage regulation module includes a voltage regulator chip U4B. A capacitor C13 is connected between pins 1 and 2 of the voltage regulator chip U4B. A resistor R17, a resistor R13, and a switch S1 are connected in series on pin 2 of the voltage regulator chip U4B. One end of the switch S1 is connected to a resistor R11 for connection with the current sharing control module. A resistor R12 and a capacitor C12 are connected in parallel at the connection point between the switch S1 and the resistor R11. Pins 5 and 7 of the voltage regulator chip U4B are connected. Pin 7 of the voltage regulator chip U4B is connected to the microcontroller U13. A resistor R21 is connected between pins 3 and 16 of the voltage regulator chip U4B. A capacitor C15 is connected at the connection point between pin 3 of the voltage regulator chip U4B and the resistor R21. A capacitor C14 is connected at the connection point between pin 16 of the voltage regulator chip U4B and the resistor R21.

4. The photovoltaic inverter parallel current sharing control circuit according to claim 1, characterized in that: The current detection module includes a current sensing chip U16. A capacitor C23 and a resistor R23 are connected in parallel between pins 3 and 4 of the current sensing chip U16. A capacitor C22 is connected to ground at pin 6 of the current sensing chip U16. A resistor R22 is connected between pins 1 and 2 of the current sensing chip U16.

5. The photovoltaic inverter parallel current sharing control circuit according to claim 1, characterized in that: The communication module includes a communication chip U25. A transistor Q13 is connected to pin 3 of the communication chip U25. A resistor R98 for connecting to a 5V voltage is connected to the collector of the transistor Q13 and the connection terminal of the communication chip U25. A resistor R99 for connecting to a serial communication interface is connected to the base of the transistor Q13. A capacitor C50 is connected to pin 8 of the communication chip U25. One end of the capacitor C50 is connected to pin 7 of the communication chip U25 through a resistor R157. A connection terminal U43 is connected to the connection terminal of the communication chip U25 through a resistor R84. Pin 2 of the connection terminal U43 is connected to pin 6 of the communication chip U25 through a resistor R85. A resistor R158 for connecting to a 5V voltage is connected to the connection terminal of the communication chip U25 and the connection terminal of the resistor R85.

Images