Optimizer circuit with single-path and double-path MPPT switching function and control method
By designing a photovoltaic optimizer circuit and control method with single and dual-channel MPPT switching function, the problems of poor stability and low efficiency of traditional photovoltaic optimizer systems are solved, and high-efficiency power conversion of photovoltaic modules is achieved under both shading and unshading conditions, thereby improving the overall performance of the system.
Patent Information
- Application Number
- CN202411149359.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-21
- Publication Date
- 2026-03-03
AI Technical Summary
When traditional photovoltaic optimizers use a single MPPT, the system stability is poor and the power generation efficiency is low, especially when the photovoltaic module is shaded, it affects the output power of the other module.
Design an optimizer circuit and control method with single or dual-channel MPPT switching function. The output power of two photovoltaic modules is processed by two independent BUCK switching circuits to realize single or dual-channel independent MPPT mode switching. The duty cycle and switching frequency of the switching transistor are adjusted according to the module status to ensure that the module operates at the maximum power point.
It improves system integration and power density, enhances MPPT efficiency, reduces current ripple, and improves system cost-effectiveness, making it particularly suitable for residential and commercial distributed photovoltaic power generation systems.
Smart Images
Figure CN121602906A_ABST
Abstract
Description
[0001] This invention relates to an optimizer circuit and control method with single / dual-channel MPPT switching function, belonging to the field of photovoltaic power generation technology. Background Technology
[0002] A buck converter, also known as a step-down converter, is a single-transistor, non-blocked DC-DC converter whose output voltage is lower than its input voltage. Buck circuits are widely used in photovoltaic power generation systems, renewable energy power supply systems, and charging / discharging applications. In photovoltaic power generation systems, because the MPPT (Maximum Power Point Tracking) of different components cannot be perfectly matched, a buck circuit is needed to achieve maximum power point tracking for each component.
[0003] The BUCK circuit is a commonly used topology in photovoltaic optimizers, characterized by its simple topology, low cost, and wide voltage reduction range.
[0004] With the continuous development of photovoltaic power generation technology, distributed photovoltaic power generation systems and maximum power point tracking (MPPT) technology can ensure that each photovoltaic module operates at its maximum power point, resulting in high power generation efficiency and high system reliability. However, traditional dual-module photovoltaic optimizers typically use a single-channel MPPT. When one of the two modules is shaded, adjusting the MPPT output power will affect the output power of the other module.
[0005] A novel technical solution is proposed, which uses two independent BUCK conversion circuits to process the output power of two photovoltaic modules, thereby enabling the two photovoltaic modules to operate in a dual-path independent MPPT mode. When one or both modules are simultaneously shaded, the dual-path MPPT mode is used to improve MPPT efficiency. When the modules are not shaded, the single-path MPPT mode is used to improve system efficiency. This solution is particularly suitable for application in residential and commercial distributed photovoltaic power generation systems. Summary of the Invention
[0006] This invention addresses the problems of poor system stability and low power generation efficiency in traditional photovoltaic optimizers that use a single MPPT, by providing an optimizer circuit and control method with single / dual MPPT switching function.
[0007] The technical solution adopted by the present invention to solve the above-mentioned technical problems is to provide an optimizer circuit and control method with single and dual-channel MPPT switching function.
[0008] The optimizer circuit with single / dual-channel MPPT switching function consists of a first photovoltaic module (PV1), a second photovoltaic module (PV2), a first switching transistor (S1), a second switching transistor (S2), a first freewheeling diode (D1), a second freewheeling diode (D2), a first output filter capacitor (C2), a second output filter capacitor (C4), a first power inductor (L1), a second power inductor (L2), a first input filter capacitor (C1), a second input filter capacitor (C2), an output positive terminal (UOUT+), and an output positive terminal (UOUT-).
[0009] The positive terminal of the second photovoltaic module (PV2) is connected to the source of the second switching transistor (S1) and the positive terminal of the second input filter capacitor (C2). The drain of the second switching transistor (S1) is connected to one end of the second power inductor (L2) and the cathode of the first freewheeling diode (D2). The other end of the second power inductor (L2) is connected to the positive output terminal. The positive terminal of the first photovoltaic module (PV1) is connected to the negative terminal of the second photovoltaic module (PV2), the cathode of the first freewheeling diode (D1), the negative terminal of the second input filter capacitor (C2), the anode of the second freewheeling diode (D2), the positive terminal of the first input filter capacitor (C1), and the positive terminal of the first output filter capacitor (C4). The negative terminal of the first photovoltaic module (PV1) is connected to the drain of the first switching transistor (S1) and the negative terminal of the first input filter capacitor (C1). The source of the first switching transistor (S1) is connected to the anode of the first freewheeling diode (D1) and one end of the winding of the first power inductor (L1). The other end of the winding of the first power inductor (L1) is connected to the negative terminal of the first output filter capacitor (C4) and the output terminal (UOUT-). The drain of the second switching transistor (S1) is connected to one end of the second power inductor (L2) and the cathode of the first freewheeling diode (D2). The other end of the second power inductor (L2) is connected to the output positive terminal.
[0010] The optimizer circuit and control method with single / dual-channel MPPT switching function can adopt one of the following three control methods: 1. An optimizer circuit and control method with single / dual-channel MPPT switching function, characterized in that: the first switch (S1) and the second switch (S2) have the same switching frequency; the output of the first photovoltaic module (PV1) is achieved by adjusting the duty cycle of the first switch (S1); the output of the first photovoltaic module (PV2) is achieved by adjusting the duty cycle of the first switch (S2); and the circuit operates in dual-channel MPPT mode, so that the first photovoltaic module and the second photovoltaic module operate at the maximum power point. 2. An optimizer circuit and control method with single and dual-channel MPPT switching function, characterized in that: the first photovoltaic module and the second photovoltaic module are connected in series, and the output of the first photovoltaic module (PV1) and the first photovoltaic module (PV2) are realized by adjusting the duty cycle of the first switching transistor (S1) separately, so that the circuit works in single-channel MPPT mode, and the first photovoltaic module and the second photovoltaic module work at the maximum power point; 3. An optimizer circuit and control method with single and dual-channel MPPT switching function, characterized in that: the first photovoltaic module and the second photovoltaic module are connected in series, and the output of the first photovoltaic module (PV1) and the first photovoltaic module (PV2) are realized by adjusting the duty cycle of the first switching transistor (S1) separately, so that the circuit works in single-channel MPPT mode, and the first photovoltaic module and the second photovoltaic module work at the maximum power point; Preferably, the optimizer circuit includes: 1. A DC sampling module that collects the voltage and current of the first photovoltaic module and the second photovoltaic module in real time; 2. The MPPT control module determines whether the current voltage of the first photovoltaic module and the second photovoltaic module both meet the preset system start-up threshold. If they do, the system is determined to be in the start-up and running state, and the current power of the first photovoltaic module and the current power of the second photovoltaic module are calculated. Otherwise, the system is determined to be in the standby state or the fault state.
[0011] Preferably, if the system is currently in operation, when the current power of the first photovoltaic module and the current power of the second photovoltaic module are close, the switch control module controls the closing of the first switch module and the second switch module. The MPPT control module includes: the positive terminal of the second photovoltaic module (PV2) is connected to the source of the second switching transistor (S2) and the positive terminal of the second input filter capacitor (C2); the drain of the second switching transistor (S2) is connected to one end of the second power inductor (L2) and the cathode of the first freewheeling diode (D2); and the other end of the second power inductor (L2) is connected to the output positive terminal. The positive terminal of the first photovoltaic module (PV1) is connected to the negative terminal of the second photovoltaic module (PV2), the cathode of the first freewheeling diode (D1), the negative terminal of the second input filter capacitor (C2), the anode of the second freewheeling diode (D2), the positive terminal of the first input filter capacitor (C1), and the positive terminal of the first output filter capacitor (C4). The negative terminal of the first photovoltaic module (PV1) is connected to the drain of the first switching transistor (S1) and the negative terminal of the first input filter capacitor (C1). The source of the first switching transistor (S1) is connected to the anode of the first freewheeling diode (D1) and one end of the winding of the first power inductor (L1). The other end of the winding of the first power inductor (L1) is connected to the negative terminal of the first output filter capacitor (C4) and the output terminal (UOUT-). The drain of the second switching transistor (S1) is connected to one end of the second power inductor (L2) and the cathode of the first freewheeling diode (D2). The other end of the second power inductor (L2) is connected to the output positive terminal.
[0012] Preferably, if the current system is in standby or fault state, when the current voltage of the first photovoltaic module and the current voltage of the second photovoltaic module are close, the second switch (S2) and the first switch (S1) of the MPPT control module are closed, and the first photovoltaic module and the second photovoltaic module operate in single-channel MPPT mode. If the current voltage of the first photovoltaic module is greater than the current voltage of the second photovoltaic module, the switching frequencies of the first switch (S1) and the second switch (S2) of the MPPT control module are the same. The output of the first photovoltaic module (PV1) is achieved by adjusting the duty cycle of the first switch (S1), and the output of the first photovoltaic module (PV2) is achieved by adjusting the duty cycle of the first switch (S2). The first photovoltaic module and the second photovoltaic module work in dual-channel MPPT mode. If the current voltage of the first photovoltaic module is less than the current voltage of the second photovoltaic module, the switching frequencies of the first switch (S1) and the second switch (S2) of the control module are the same. The output of the first photovoltaic module (PV1) is achieved by adjusting the duty cycle of the first switch (S1), and the output of the first photovoltaic module (PV2) is achieved by adjusting the duty cycle of the first switch (S2). The first photovoltaic module and the second photovoltaic module work in dual-channel MPPT mode.
[0013] To achieve the above objectives, the present invention provides an optimizer circuit and control method with single / dual-channel MPPT switching function, the method comprising: The current power of the first photovoltaic module and the second photovoltaic module are monitored in real time respectively; When the current power of the first photovoltaic module and the current power of the second photovoltaic module are close, the first switch (S1) and the first switch (S2) are closed simultaneously, so that the first photovoltaic module and the second photovoltaic module operate in single-channel MPPT mode. When the current power of the first photovoltaic module is greater than the current power of the second photovoltaic module, the first switch module is closed and the second switch module is opened, so that the first photovoltaic module and the second photovoltaic module work in dual-channel MPPT mode. When the current power of the first photovoltaic module is less than the current power of the second photovoltaic module, the system controls the disconnection of the first switch module and the closing of the second switch module to enable the first and second photovoltaic modules to operate in dual-path MPPT mode.
[0014] Compared with the prior art, the present invention provides an optimizer circuit and control method with single and dual-channel MPPT switching function, which brings the following beneficial effects: The product has higher integration and power density. It achieves power conversion of two photovoltaic modules through two independent BUCK circuits, allowing the two photovoltaic modules to work in single-channel MPPT mode or dual-channel independent MPPT mode.
[0015] When the component is shaded, it operates in dual-channel MPPT mode to improve MPPT efficiency. When the component is not shaded, it operates in single-channel MPPT mode to reduce current ripple and improve conversion efficiency, thereby achieving a higher cost-performance ratio. Attached Figure Description
[0016] Figure 1 This is a schematic diagram of an optimizer circuit system with single / dual-channel MPPT switching function according to an embodiment of the present invention.
[0017] Figure 1 Labels: PV1 and PV2 are two photovoltaic modules; S1 and S2 are the first and second switching transistors; D1 and D2 are the first and second freewheeling diodes; L1 and L2 are the first and second power inductors; C1 and C2 are the first and second input filter capacitors; C3 and C4 are the first and second output filter capacitors; Output negative terminal (UOUT-); Output positive terminal (UOUT+).
[0018] Figure 1This is a system structure diagram of the present invention. An optimizer circuit with single and dual-channel MPPT switching function is composed of a first photovoltaic module (PV1), a second photovoltaic module (PV2), a first switching transistor (S1), a second switching transistor (S2), a first freewheeling diode (D1), a second freewheeling diode (D2), a first output filter capacitor (C2), a second output filter capacitor (C4), a first power inductor (L1), a second power inductor (L2), a first input filter capacitor (C1), a second input filter capacitor (C2), an output positive terminal (UOUT+), and an output negative terminal (UOUT-).
[0019] The positive terminal of the second photovoltaic module (PV2) is connected to the source of the second switching transistor (S2) and the positive terminal of the second input filter capacitor (C2). The drain of the second switching transistor (S2) is connected to one end of the second power inductor (L2) and the cathode of the first freewheeling diode (D2). The other end of the second power inductor (L2) is connected to the output positive terminal. The positive terminal of the first photovoltaic module (PV1) is connected to the negative terminal of the second photovoltaic module (PV2), the cathode of the first freewheeling diode (D1), the negative terminal of the second input filter capacitor (C2), the anode of the second freewheeling diode (D2), the positive terminal of the first input filter capacitor (C1), and the positive terminal of the first output filter capacitor (C4). The negative terminal of the first photovoltaic module (PV1) is connected to the drain of the first switching transistor (S1) and the negative terminal of the first input filter capacitor (C1). The source of the first switching transistor (S1) is connected to the anode of the first freewheeling diode (D1) and one end of the winding of the first power inductor (L1). The other end of the winding of the first power inductor (L1) is connected to the negative terminal of the first output filter capacitor (C4) and the output terminal (UOUT-). The drain of the second switching transistor (S1) is connected to one end of the second power inductor (L2) and the cathode of the first freewheeling diode (D2). The other end of the second power inductor (L2) is connected to the output positive terminal. Detailed Implementation
[0020] The optimizer circuit and control method with single / dual-channel MPPT switching function can adopt one of the following three control methods: 1. An optimizer circuit and control method with single and dual-channel MPPT switching function, characterized in that: the first switch (S1) and the second switch (S2) have the same switching frequency, the output of the first photovoltaic module (PV1) is realized by adjusting the duty cycle of the first switch (S1), and the output of the first photovoltaic module (PV2) is realized by adjusting the duty cycle of the first switch (S2), operating in dual-channel MPPT mode, so that the first photovoltaic module and the second photovoltaic module operate at the maximum power point; 2. An optimizer circuit and control method with single and dual-channel MPPT switching function, characterized in that: the first photovoltaic module and the second photovoltaic module are connected in series, and the output of the first photovoltaic module (PV1) and the first photovoltaic module (PV2) are realized by adjusting the duty cycle of the first switching transistor (S1) separately, so that the circuit works in single-channel MPPT mode, and the first photovoltaic module and the second photovoltaic module work at the maximum power point; 3. An optimizer circuit and control method with single and dual-channel MPPT switching function, characterized in that: the first photovoltaic module and the second photovoltaic module are connected in series, and the output of the first photovoltaic module (PV1) and the first photovoltaic module (PV2) are realized by adjusting the duty cycle of the first switching transistor (S1) separately, so that the circuit works in single-channel MPPT mode, and the first photovoltaic module and the second photovoltaic module work at the maximum power point; If the current voltage of the first photovoltaic module is greater than the current voltage of the second photovoltaic module, the switching frequencies of the first switch (S1) and the second switch (S2) of the MPPT control module are the same. The output of the first photovoltaic module (PV1) is achieved by adjusting the duty cycle of the first switch (S1), and the output of the first photovoltaic module (PV2) is achieved by adjusting the duty cycle of the first switch (S2). The first photovoltaic module and the second photovoltaic module work in dual-channel MPPT mode. If the current voltage of the first photovoltaic module is less than the current voltage of the second photovoltaic module, the switching frequencies of the first switch (S1) and the second switch (S2) of the control module are the same. The output of the first photovoltaic module (PV1) is achieved by adjusting the duty cycle of the first switch (S1), and the output of the first photovoltaic module (PV2) is achieved by adjusting the duty cycle of the first switch (S2). The first photovoltaic module and the second photovoltaic module work in dual-channel MPPT mode.
[0021] Although preferred embodiments of the invention have been disclosed for illustrative purposes, those skilled in the art will understand that… Those skilled in the art will recognize that, without departing from the scope and spirit of the invention as disclosed in the appended claims, In such cases, various improvements, additions, and replacements are possible.
Claims
1. An optimizer circuit and control method with single / dual-channel MPPT switching function, characterized in that: It comprises a first photovoltaic module (PV1), a second photovoltaic module (PV2), a first switching transistor (S1), a second switching transistor (S2), a first freewheeling diode (D1), a second freewheeling diode (D2), and a first output filter capacitor (C1). The second output filter capacitor (C2) is composed of a first power inductor (L1) and a second power inductor (L2). It also comprises a first input filter capacitor (C1) and a second input filter capacitor (C2).
2. An optimizer circuit and control method with single / dual-channel MPPT switching function, characterized in that: The first switch (S1) and the second switch (S2) have the same switching frequency, so that the first photovoltaic module and / or the second photovoltaic module can switch between single-channel MPPT mode and dual-channel MPPT mode.
3. An optimizer circuit and control method with single / dual-channel MPPT switching function, characterized in that: The first switch (S1) and the second switch (S2) have the same switching frequency. The output of the first photovoltaic module (PV1) is achieved by adjusting the duty cycle of the first switch (S1), and the output of the first photovoltaic module (PV2) is achieved by adjusting the duty cycle of the first switch (S2). The system operates in dual-path MPPT mode, so that the first photovoltaic module and the second photovoltaic module operate at the maximum power point.
4. An optimizer circuit and control method with single / dual-channel MPPT switching function, characterized in that: The first photovoltaic module and the second photovoltaic module are connected in series. The output of the first photovoltaic module (PV1) and the first photovoltaic module (PV2) is realized by adjusting the duty cycle of the first switching transistor (S1) individually, so that the circuit works in single-channel MPPT mode, and the first photovoltaic module and the second photovoltaic module work at the maximum power point.