DCDC and MPPT compatible design circuit

Abstract

The invention discloses a DCDC and MPPT compatible design circuit, which comprises a DC / AC converter, a first power connection module and a second power connection module, and is characterized in that the DC / AC converter is connected with a DC bus in parallel, and the DC bus is connected with the first power connection module and the second power connection module in parallel; each of the first power connection module and the second power connection module comprises at least two BUCK-BOOST circuit modules which are connected in parallel, the input ends of the BUCK-BOOST circuit modules are connected to the positive electrode and the negative electrode of a power supply module in parallel through a common mode inductor L, the output ends of the multiple BUCK-BOOST circuit modules are sequentially arranged in parallel, and a parallel circuit is connected with the direct current bus in parallel.

Description

Technical Field

[0001] The invention relates to the technical field of power electronics, and in particular to a DCDC and MPPT compatible design circuit. Background Art

[0002] The photovoltaic storage hybrid converter generally includes two DC-DC conversion units: DCDC (DC to DC) and MPPT (maximum power point tracking of photovoltaic panels). The DCDC conversion is generally a half-bridge BUCK-BOOST topology, and the MPPT is generally a BOOST topology. The difference between BUCK-BOOST and BOOST topologies is as follows: Figure 1 As shown, there is only one difference between the switch tube Q and the diode D. In order to adapt to more battery capacity configurations, the operating voltage range and current range of the photovoltaic and battery of the general photovoltaic storage hybrid inverter are basically the same, but its different topologies can only be targeted to the photovoltaic panel or battery. Figure 2 When different numbers of photovoltaic panels or batteries are connected, the connection method is relatively simple, resulting in poor circuit flexibility. In addition, due to the influence of the circuit usage scenario, there may be large common mode noise and unstable signal transmission.

[0003] Therefore, it is necessary to provide a DCDC and MPPT compatible design circuit to solve the problems mentioned in the above background technology. Summary of the invention

[0004] To achieve the above object, the present invention provides the following technical solution: a DCDC and MPPT compatible design circuit, comprising: a DC / AC converter, a first power connection module and a second power connection module, the DC / AC converter is connected in parallel with a DC bus, and the first power connection module and the second power connection module are respectively connected in parallel on the DC bus;

[0005] The first power connection module and the second power connection module each include at least two parallel BUCK-BOOST circuit modules, the input end of the BUCK-BOOST circuit module is connected in parallel to the positive electrode and the negative electrode of the power supply module through a common mode inductor L, and the output ends of the plurality of BUCK-BOOST circuit modules are respectively arranged in parallel in sequence, and the parallel circuit is connected in parallel with the DC bus.

[0006] Preferably, a capacitor Cbus1 and a capacitor Cbus2 are connected in series between the DC bus and the connection ends of the first power connection module and the second power connection module.

[0007] Preferably, a capacitor C1 is connected in parallel between the input end of the BUCK-BOOST circuit module and the output end of the common-mode inductor L, and a capacitor C2 is connected in parallel between the output end of the BUCK-BOOST circuit module and the connection end of the DC bus.

[0008] Preferably, the common-mode inductor L has a first common-mode inductor coil and a second common-mode inductor coil, two ends of the first common-mode inductor coil are respectively connected in series to the positive electrode of the power supply module and the first input end of the BUCK-BOOST circuit module, and two ends of the second common-mode inductor coil are respectively connected in series to the negative electrode of the power supply module and the second input end of the BUCK-BOOST circuit module.

[0009] Preferably, the BUCK-BOOST circuit module comprises: a switch tube Q1, a switch tube Q2 and an inductor L1, wherein the inductor L1 and the switch tube Q2 are sequentially connected in series between the DC bus and the positive electrode connection end of the power supply module, the D pole of the switch tube Q2 is connected to the positive electrode of the DC bus, and the S pole of the switch tube Q2 is connected to the inductor L1;

[0010] The switch tube Q1 is connected in parallel between the connection end of the inductor L1 and the switch tube Q2 and the connection end of the capacitor C1 and the capacitor C2, the D pole of the switch tube Q1 is connected to the connection end of the inductor L1 and the switch tube Q2, and the S pole of the switch tube Q1 is connected to the connection end of the capacitor C1 and the capacitor C2;

[0011] The G poles of the switch tube Q1 and the switch tube Q2 are grounded.

[0012] Preferably, diodes are connected in parallel between the D pole and the S pole of the switch tube Q1 and the switch tube Q2, respectively.

[0013] Preferably, the power supply module is at least one of a battery or a photovoltaic panel.

[0014] Compared with the prior art, the present invention provides a DCDC and MPPT compatible design circuit, which has the following beneficial effects:

[0015] In the present invention, by arranging BUCK-BOOST circuit modules in both the first power connection module and the second power connection module, the current input to the MPPT circuit of the hybrid converter is boosted or bucked, and the corresponding control mode is selected according to the different DC inputs, so that the use is more flexible; at the same time, by connecting the common-mode inductor in the circuit, the common-mode noise introduced by the photovoltaic panel or battery or the external environment can be effectively suppressed, the overall anti-interference ability of the circuit is improved, and the current impact is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Schematic diagram of BOOST topology and BUCK-BOOST topology;

[0017] Figure 2 It is a schematic diagram of the DC side circuit structure of a traditional hybrid converter;

[0018] Figure 3 A schematic diagram of a DCDC and MPPT compatible circuit design showing a hybrid access structure of photovoltaic panels and batteries;

[0019] Figure 4 A schematic diagram of a pure battery access structure for a DCDC and MPPT compatible design circuit;

[0020] Figure 5 A schematic diagram of a DCDC and MPPT compatible circuit design with a pure photovoltaic panel access structure;

[0021] In the figure: 1. DC / AC converter; 2. First power connection module; 3. Second power connection module; 4. BUCK-BOOST circuit module; 5. DC bus. DETAILED DESCRIPTION

[0022] Example 1: Please refer to Figure 3 The present invention provides a DCDC and MPPT compatible design circuit, comprising: a DC / AC converter 1, a first power connection module 2 and a second power connection module 3, wherein the DC / AC converter 1 is connected in parallel with a DC bus 5, and the first power connection module 2 and the second power connection module 3 are respectively connected in parallel to the DC bus 5;

[0023] The first power connection module 2 and the second power connection module 3 each include at least two BUCK-BOOST circuit modules 4 connected in parallel, the input end of the BUCK-BOOST circuit module 4 is connected in parallel to the positive and negative electrodes of the power supply module through a common-mode inductor L, and the output ends of the plurality of BUCK-BOOST circuit modules 4 are respectively arranged in parallel in sequence, and the parallel lines are connected in parallel to the DC bus 5.

[0024] Among them, by setting BUCK-BOOST circuit modules 4 in both the first power connection module 2 and the second power connection module 3, the current input to the hybrid converter MPPT circuit is boosted or bucked, and the corresponding control mode is selected according to the different DC inputs, which is more flexible to use.

[0025] Furthermore, a capacitor Cbus1 and a capacitor Cbus2 are connected in series between the DC bus 5 and the connection ends of the first power connection module 2 and the second power connection module 3 .

[0026] Furthermore, a capacitor C1 is connected in parallel between the input end of the BUCK-BOOST circuit module 4 and the output end of the common mode inductor L, and a capacitor C2 is connected in parallel between the output end of the BUCK-BOOST circuit module 4 and the connection end of the DC bus 5.

[0027] Furthermore, the common-mode inductor L has a first common-mode inductor coil and a second common-mode inductor coil, two ends of the first common-mode inductor coil are respectively connected in series to the positive electrode of the power supply module and the first input end of the BUCK-BOOST circuit module 4, and two ends of the second common-mode inductor coil are respectively connected in series to the negative electrode of the power supply module and the second input end of the BUCK-BOOST circuit module 4.

[0028] Further, the BUCK-BOOST circuit module 4 includes: a switch tube Q1, a switch tube Q2 and an inductor L1, the inductor L1 and the switch tube Q2 are sequentially connected in series between the DC bus 5 and the positive electrode connection end of the power supply module, the D pole of the switch tube Q2 is connected to the positive electrode of the DC bus 5, and the S pole of the switch tube Q2 is connected to the inductor L1;

[0029] The switch tube Q1 is connected in parallel between the connection end of the inductor L1 and the switch tube Q2 and the connection end of the capacitor C1 and the capacitor C2, the D pole of the switch tube Q1 is connected to the connection end of the inductor L1 and the switch tube Q2, and the S pole of the switch tube Q1 is connected to the connection end of the capacitor C1 and the capacitor C2;

[0030] The G poles of the switch tube Q1 and the switch tube Q2 are grounded.

[0031] Furthermore, diodes are connected in parallel between the D pole and the S pole of the switch tube Q1 and the switch tube Q2 respectively.

[0032] Furthermore, the power supply module is at least one of a battery or a photovoltaic panel.

[0033] In this embodiment, Figure 3 The input ends of the first power connection module 2 and the second power connection module 3 are respectively connected in parallel with the positive and negative electrodes of the battery and the photovoltaic panel through the common mode inductor L, wherein the positive and negative electrodes of the photovoltaic panel are connected to the first input end and the second input end of the BUCK-BOOST circuit module 4 in a one-to-one correspondence. When the battery is connected, the first input end and the second input end of the BUCK-BOOST circuit module 4 are respectively connected in parallel, and the parallel circuit is connected to the positive and negative electrodes of the battery in a corresponding manner, and then the corresponding control mode is selected according to the different DC inputs connected, which is more flexible to use.

[0034] In this embodiment, the first power connection module 2 and the second power connection module 3 are connected to the battery and the photovoltaic panel, respectively, to show that each BUCK-BOOST circuit module 4 can be connected to different power supply modules, which is not the only connection method. Different numbers of BUCK-BOOST circuit modules 4 can also be selected in the first power connection module 2 or the second power connection module 3 to connect to the battery and the photovoltaic panel, respectively, to improve the applicability of the circuit.

[0035] Example 2: Figure 4 , which is different from Embodiment 1 in that: the BUCK-BOOST circuit modules 4 in the first power connection module 2 and the second power connection module 3 are connected to the positive and negative electrodes of the battery through a common mode inductor L, and the first input terminal and the second input terminal of the BUCK-BOOST circuit module 4 in the first power connection module 2 or the second power connection module 3 are respectively connected in parallel, and the parallel lines are connected to the positive and negative electrodes of the battery accordingly.

[0036] It should be explained that when a pure battery needs to be connected to the DC / AC converter 1, the multiple parallel BUCK-BOOST circuit modules 4 can be selectively connected to the battery for step-up or step-down conversion, charging and discharging the battery, and realizing power conversion of the battery output current.

[0037] Example 3: Figure 5 The difference between the embodiment 1 and the embodiment 1 is that each of the BUCK-BOOST circuit modules 4 in the first power connection module 2 and the second power connection module 3 is connected in parallel with a photovoltaic panel, and the positive and negative electrodes of the photovoltaic panel are connected to the first input terminal and the second input terminal of the BUCK-BOOST circuit module 4 in a one-to-one correspondence.

[0038] It should be explained that when pure photovoltaic access to the DC / AC converter 1 is required, the multiple parallel BUCK-BOOST circuit modules 4 are each connected to the photovoltaic panel. At this time, the BUCK-BOOST circuit module 4 only uses the boost function to perform power conversion on the output current of the photovoltaic panel.

[0039] What is described above is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A DCDC and MPPT compatible design circuit, characterized in that: include: A DC / AC converter (1), a first power connection module (2) and a second power connection module (3), wherein the DC / AC converter (1) is connected in parallel with a DC bus (5), and the first power connection module (2) and the second power connection module (3) are respectively connected in parallel with the DC bus (5); The first power connection module (2) and the second power connection module (3) each comprise at least two parallel BUCK-BOOST circuit modules (4), the input end of the BUCK-BOOST circuit module (4) being connected in parallel to the positive electrode and the negative electrode of the power supply module via a common mode inductor L, the output ends of the plurality of BUCK-BOOST circuit modules (4) being arranged in parallel in sequence, and the parallel circuits being connected in parallel to the DC bus (5).

2. A DCDC and MPPT compatible design circuit according to claim 1, characterized in that: A capacitor Cbus1 and a capacitor Cbus2 are connected in series between the DC bus (5) and the connection ends of the first power connection module (2) and the second power connection module (3).

3. A DCDC and MPPT compatible design circuit according to claim 2, characterized in that: A capacitor C1 is connected in parallel between the input end of the BUCK-BOOST circuit module (4) and the output end of the common-mode inductor L, and a capacitor C2 is connected in parallel between the output end of the BUCK-BOOST circuit module (4) and the connection end of the DC bus (5).

4. A DCDC and MPPT compatible design circuit according to claim 1, characterized in that: The common-mode inductor L comprises a first common-mode inductor coil and a second common-mode inductor coil, wherein two ends of the first common-mode inductor coil are respectively connected in series to the positive electrode of the power supply module and the first input end of the BUCK-BOOST circuit module (4), and two ends of the second common-mode inductor coil are respectively connected in series to the negative electrode of the power supply module and the second input end of the BUCK-BOOST circuit module (4).

5. A DCDC and MPPT compatible design circuit according to claim 3, characterized in that: The BUCK-BOOST circuit module (4) comprises: a switch tube Q1, a switch tube Q2 and an inductor L1, wherein the inductor L1 and the switch tube Q2 are sequentially connected in series between the DC bus (5) and the positive electrode connection end of the power supply module, the D pole of the switch tube Q2 is connected to the positive electrode of the DC bus (5), and the S pole of the switch tube Q2 is connected to the inductor L1; The switch tube Q1 is connected in parallel between the connection end of the inductor L1 and the switch tube Q2 and the connection end of the capacitor C1 and the capacitor C2, the D pole of the switch tube Q1 is connected to the connection end of the inductor L1 and the switch tube Q2, and the S pole of the switch tube Q1 is connected to the connection end of the capacitor C1 and the capacitor C2; The G poles of the switch tube Q1 and the switch tube Q2 are grounded.

6. A DCDC and MPPT compatible design circuit according to claim 5, characterized in that: Diodes are connected in parallel between the D pole and the S pole of the switch tube Q1 and the switch tube Q2 respectively.

7. A DCDC and MPPT compatible design circuit according to claim 1, characterized in that: The power supply module is at least one of a battery or a photovoltaic panel.

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