Voltage gain extensible Boost converter suitable for photovoltaic power generation

Abstract

The utility model provides a voltage gain extensible Boost converter suitable for photovoltaic power generation, which comprises a direct current input source uin, a basic Boost converter and n extension units, and each extension unit is composed of two capacitors and two diodes. According to the utility model, the input and output voltage gain of the basic Boost converter can be effectively improved, and the condition that an extreme duty ratio is adopted for realizing relatively large voltage gain is avoided. The expansion unit structure can realize high-gain boost of the converter, and different numbers of expansion units can be adopted according to specific application occasions, so that different voltage gain requirements are realized, and the applicability of the converter in a high-boost occasion is effectively expanded.

Description

Technical Field

[0001] The utility model relates to a DC-DC converter, in particular to a voltage-gain expandable Boost converter suitable for photovoltaic power generation. Background Art

[0002] At present, photovoltaic power generation and energy storage batteries are widely used in the power industry. However, due to the low output voltage level of the DC power supply of the above new energy power generation methods and the high grid-connected voltage, the voltage gain of traditional DC-DC converters is difficult to meet the high step-up requirements. Therefore, a high-gain DC-DC converter is needed to convert the low voltage of the new energy power supply into the high voltage required for grid connection.

[0003] In the prior art, the Boost converter is the most common step-up converter, which has a simple structure, strong step-up ability, and the input inductor ensures the continuity of the input current, making it easier to achieve the maximum power tracking of the photovoltaic panel. However, the basic Boost converter has limited step-up ability. Although a high duty cycle can achieve a high voltage gain in an ideal situation, in actual situations, due to the influence of the parasitic parameters of the converter, its voltage gain cannot achieve the high gain in the ideal situation, and instead, the voltage gain will decrease with the increase of the duty cycle. To improve the voltage gain, for example, the patent document with the application publication number CN116667666A discloses a high-gain Boost converter and its control method. This converter realizes the ZVS of the switching tube by using the resonance of parasitic capacitors and inductors, achieves high gain and reduces the voltage stress of the devices by constructing a voltage multiplier unit, and has five working modes in one cycle, expanding the application scenarios. At the same time, the parallel design of inductors can be used to reduce the output current ripple in the CCM mode. However, this converter contains more active switches, the control method is complex, and a large number of inductor elements are included in the structure, which greatly increases the volume and cost of the converter. In addition, its structure is not expandable, the voltage gain is relatively fixed, and it is difficult to meet the high step-up requirements in different scenarios. Summary of the Utility Model

[0004] To solve the technical problems such as the low voltage gain, insufficient step-up ability, and small adjustable range of voltage gain of the basic Boost converter, the utility model proposes a voltage-gain expandable DC-DC converter suitable for photovoltaic power generation, which realizes high voltage gain and has multi-stage gain adjustment ability.

[0005] To achieve the above object, the technical solution adopted by the utility model is as follows:

[0006] A voltage-gain expandable Boost converter suitable for photovoltaic power generation, characterized in that: the converter includes a DC input source u in , a basic Boost converter,n an extended unit, n where n is a natural number and the value range is n≥1; among which:

[0007] The basic Boost converter includes an inductor L1, a power switch S1, a capacitor C1, and a diode D1; their connection form is as follows: the left end of the inductor L1 is connected to the positive pole of the DC input source, the right end of the inductor L1 is connected to the drain of the power switch S1, the source of the power switch S1 is connected to the negative pole of the DC input source, the gate of the power switch S1 is connected to the controller, the anode of the diode D1 is connected to the right end of the inductor L1, the cathode of the diode D1 is connected to the upper end of the capacitor C1, and the lower end of the capacitor C1 is connected to the source of the power switch S1 and the negative pole of the DC input source;

[0008] The extended unit includes two diodes and two capacitors;

[0009] When n = 1, the first extended unit includes a first capacitor C 11 , a second capacitor C 12 , a first diode D 11 , and a second diode D 12 ; among which, the left end of the second capacitor C 12 of the first extended unit is connected to the anode of the diode D1 of the basic Boost converter, the right end of the second capacitor C 12 is connected to the anode of the first diode D 11 and the cathode of the second diode D 12 , the anode of the second diode D 12 is connected to the cathode of the diode D1, the upper end of the first capacitor C 11 is connected to the cathode of the first diode D 11 , and the lower end of the first capacitor C 11 is connected to the anode of the second diode D 12 to form the first extended unit;

[0010] When n = 2, the left end of the second capacitor C 22 of the second extended unit is connected to the left end of the second capacitor C 12 of the first extended unit, the anode of the second diode D 22 of the second extended unit is connected to the cathode of the first diode D 11 of the first extended unit, and the upper end of the first capacitor C 21 of the second extended unit is connected to the first diode D 11 of the first extended unitFor the cathode connection, when n > 2, each extended unit is connected in sequence from bottom to top in this way until the left end of the second capacitor of the nth extended unit is connected to the left end of the second capacitor of the (n - 1)th extended unit, the anode of the second diode of the nth extended unit is connected to the cathode of the first diode of the (n - 1)th extended unit, and the upper end of the first capacitor of the nth extended unit is connected to the cathode of the first diode of the (n - 1)th extended unit;

[0011] Load R Both ends of which are respectively connected to the n first capacitor in the C n1 upper end and the lower end of the capacitor C1 in the basic Boost converter.

[0012] When two extended units are used, when the power switch S1 is turned on, the second diode D of the first extended unit 12 and the second diode D of the second extended unit 22 are turned on, the diode D1 of the basic Boost converter, the first diode D of the first extended unit 11 and the first diode D of the second extended unit 21 are turned off, the input voltage u in is applied to the inductor L1, the current of the inductor L1 rises, the diode D1 of the basic Boost converter and the first diode D of the first extended unit 11 and the first diode D of the second extended unit 21 bear reverse voltage and are cut off, the second capacitor C of the first extended unit 12 and the second capacitor C of the second extended unit 22 are charged, and the capacitor C1 and the first capacitor C of the first extended unit 11 and the first capacitor C of the second extended unit 21 discharge to supply power to the load.

[0013] When two extended units are used, when the power switch S1 is turned off, the second diode D of the first extended unit 12 and the second diode D of the second extended unit 22 are turned off, the diode D1 of the basic Boost converter, the first diode D of the first extended unit 11 and the first diode D of the second extended unit 21 are turned on, the current of the inductor L1 drops, the input voltage u in the inductor L1 and the second capacitor C of the first extended unit 12 and the second capacitor C of the second extended unit 22Discharge through diode D1 of the basic Boost converter and the first diode D of the first extended unit 11 and the first diode D of the second extended unit 21 Charge capacitor C1 of the basic Boost converter and the second capacitor C of the first extended unit 12 and the second capacitor C of the second extended unit 22 while powering the load.

[0014] Its input-output gain is adjusted by regulating the number of extended units, achieving high-gain multi-stage voltage regulation ability. The voltage gain that each extended unit can improve is: 1 / (1 - D), and the overall voltage gain of the converter M is: ( n + 1) / (1 - D).

[0015] A voltage-gain expandable Boost converter applicable to photovoltaic power generation according to the present utility model has the following technical effects:

[0016] 1) It can effectively improve the input-output voltage gain of the basic Boost converter, avoiding the situation of using an extreme duty cycle to achieve a large voltage gain.

[0017] 2) On the premise of ensuring the continuity of the input current of the basic Boost converter, by adding extended units in the present utility model, high-gain boost of the converter can be realized, and the gain is adjustable, which is more suitable for high-boost occasions under photovoltaic power generation.

[0018] 3) The present utility model can adopt different numbers of extended units according to specific application scenarios, so as to achieve different voltage gain requirements, effectively expanding the applicability of the converter. Description of the Drawings

[0019] The following further illustrates the present utility model in conjunction with the drawings and embodiments:

[0020] Figure 1 is the specific circuit schematic diagram of the present utility model with 2 extended units.

[0021] Figure 2 is the specific circuit schematic diagram of the present utility model with n extended units.

[0022] Figure 3 is the comparison curve of the voltage gain of the present utility model with 1, 2, and 4 extended units and the voltage gain of the basic Boost converter. Detailed Embodiment

[0023] Figure 1A voltage gain scalable Boost converter applicable to photovoltaic power generation includes a DC input source u in , a basic Boost converter, and two expansion units; among them:

[0024] The basic Boost converter includes an inductor L1, a power switch S1, a capacitor C1, and a diode D1; their connection form is as follows: the left end of the inductor L1 is connected to the positive pole of the DC input source, the right end of the inductor L1 is connected to the drain of the power switch S1, the source of the power switch S1 is connected to the negative pole of the DC input source, the gate of the power switch S1 is connected to the controller, the anode of the diode D1 is connected to the right end of the inductor L1, the cathode of the diode D1 is connected to the upper end of the capacitor C1, and the lower end of the capacitor C1 is connected to the source of the power switch S1 and the negative pole of the DC input source; the expansion unit includes two diodes and two capacitors;

[0025] The first expansion unit includes a capacitor C 11 , a capacitor C 12 , a diode D 11 , a diode D 12 ; among them, the left end of the capacitor C 12 of the first expansion unit is connected to the anode of the diode D1 of the basic Boost converter, the right end of the capacitor C 12 is connected to the anode of the diode D 11 and the cathode of the diode D 12 , the anode of the diode D 12 is connected to the cathode of the diode D1, the upper end of the capacitor C 11 is connected to the cathode of the diode D 11 , and the lower end of the capacitor C 11 is connected to the anode of the diode D 12 to form the first expansion unit;

[0026] The second expansion unit includes a capacitor C 21 , a capacitor C 22 , a diode D 21 , a diode D 22 ; among them, the left end of the capacitor C 22 of the second expansion unit is connected to the left end of the capacitor C 12 of the first expansion unit, the right end of the capacitor C 22 is connected to the anode of the diode D 21 and the cathode of the diode D 22 , the anode of the diode D 22 of the second expansion unit is connected to the cathode of the diode D 11 of the first expansion unit, the upper end of the capacitor C 21 of the second expansion unit is connected to the cathode of the diode D 11 , and the lower end of the capacitor C 21 is connected to the diode D22 The anode connection forms the second extended unit;

[0027] Load R Both ends are respectively connected to the 2 capacitor in the C 21 upper end of the and the lower end of the capacitor C1 in the basic Boost converter.

[0028] When two extended units are adopted, when the power switch S1 is turned on, the diodes D 12 , D 22 conduct, the diodes D1 and D 11 , D 21 are turned off, the input voltage u in is applied to the inductor L1, the current of the inductor L1 rises, and the diodes D1 and the diode D of the first extended unit 11 and the diode D of the second extended unit 21 bear the reverse voltage and are cut off. The capacitor C of the first extended unit 12 and the capacitor C of the second extended unit 22 are charged, and the capacitor C1, the capacitor C of the first extended unit 11 and the capacitor C of the second extended unit 21 discharge to supply power to the load.

[0029] When two extended units are adopted, when the power switch S1 is turned off, the diodes D 12 , D 22 are turned off, the diodes D1 and D 11 , D 21 conduct, the current of the inductor L1 drops, and the input voltage u in , the inductor L1, and the capacitor C of the first extended unit 12 and the capacitor C of the second extended unit 22 discharge. Through the diodes D1 and the diode D of the first extended unit 11 and the diode D of the second extended unit 21 charge the capacitor C1 and the capacitor C of the first extended unit 12 and the capacitor C of the second extended unit 22 and supply power to the load at the same time.

[0030] Figure 2 As shown, a voltage gain scalable Boost converter applicable to photovoltaic power generation includes a DC input source u in , a basic Boost converter, n extended units; where:

[0031] The basic Boost converter includes an inductor L1, a power switch S1, a capacitor C1, and a diode D1; their connection form is as follows: The left end of the inductor L1 is connected to the positive pole of the DC input source, the right end of the inductor L1 is connected to the drain of the power switch S1, the source of the power switch S1 is connected to the negative pole of the DC input source, the gate of the power switch S1 is connected to the controller, the anode of the diode D1 is connected to the right end of the inductor L1, the cathode of the diode D1 is connected to the upper end of the capacitor C1, and the lower end of the capacitor C1 is connected to the source of the power switch S1 and the negative pole of the DC input source; The expansion unit includes two diodes and two capacitors.

[0032] The first expansion unit includes a capacitor C 11 , a capacitor C 12 , a diode D 11 , and a diode D 12 ; Among them, the left end of the capacitor C 12 of the first expansion unit is connected to the anode of the diode D1 of the basic Boost converter, the right end of the capacitor C 12 is connected to the anode of the diode D 11 and the cathode of the diode D 12 , the anode of the diode D 12 is connected to the cathode of the diode D1, the upper end of the capacitor C 11 is connected to the cathode of the diode D 11 , and the lower end of the capacitor C 11 is connected to the anode of the diode D 12 to form the first expansion unit.

[0033] The second expansion unit includes a capacitor C 21 , a capacitor C 22 , a diode D 21 , and a diode D 22 ; Among them, the left end of the capacitor C 22 of the second expansion unit is connected to the left end of the capacitor C 12 of the first expansion unit, the right end of the capacitor C 22 is connected to the anode of the diode D 21 and the cathode of the diode D 22 , the anode of the diode D 22 of the second expansion unit is connected to the cathode of the diode D 11 of the first expansion unit, the upper end of the capacitor C 21 of the second expansion unit is connected to the cathode of the diode D 11 , and the lower end of the capacitor C 21 is connected to the anode of the diode D 22 to form the second expansion unit.

[0034] n The expansion units are connected in sequence from bottom to top. That is, the capacitor C 22The left end is connected to the capacitance C of the first expansion unit. 12 At the left end, the diode D of the second expansion unit 22 The anode of is connected to the diode D of the first expansion unit 11 The cathode; and so on, until the n th expansion unit;

[0035] n is a natural number, and the value range is n ≥1, and the structures of each expansion unit are the same;

[0036] Load R The two ends of are respectively connected to the n th expansion unit capacitance C n1 The upper end is connected to the lower end of the capacitance C1 in the basic Boost converter.

[0037] When two expansion units are adopted, when the power switch S1 is turned on, the diodes D 12 、D 22 conduct, the diodes D1 and the diode D 11 、D 21 turn off, the input voltage u in is applied to the inductor L1, the current of the inductor L1 rises, and the diodes D1 and the diode D of the first expansion unit 11 and the diode D of the second expansion unit 21 bear the reverse voltage and cut off, and the capacitance C of the first expansion unit 12 and the capacitance C of the second expansion unit 22 are charged, and the capacitance C1 and the capacitance C of the first expansion unit 11 and the capacitance C of the second expansion unit 21 discharge to supply power to the load.

[0038] When two expansion units are adopted, when the power switch S1 is turned off, the diodes D 12 、D 22 turn off, the diodes D1 and the diode D 11 、D 21 conduct, the current of the inductor L1 drops, and the input voltage u in 、the inductor L1, and the capacitance C of the first expansion unit 12 and the capacitance C of the second expansion unit 22 discharge, and through the diode D1 and the diode D of the first expansion unit 11 and the diode D of the second expansion unit 21 charge the capacitance C1 and the capacitance C of the first expansion unit 12 and the capacitance C of the second expansion unit 22 and supply power to the load at the same time.

[0039] Its input and output gain is adjusted by regulating the number of expansion units, achieving the ability of high-gain multi-stage voltage regulation. The voltage gain that each expansion unit can improve is: 1 / (1 - D), and the overall voltage gain of the converter M is: ( n + 1) / (1 - D).

[0040] It can be seen that under the same duty cycle, by increasing the expansion units, the voltage gain of the converter can be effectively improved, solving the problems of low voltage gain and insufficient boosting ability of the basic Boost converter. Figure 3 As described above, only the specific embodiments of the present invention are given, but the structural features of the present invention are not limited thereto. Any changes or modifications made by those skilled in the art within the scope of the present invention are covered by the protection scope of the present invention.

[0041] It should be noted that the terms "including" and "having" and any variations thereof in the description and claims of the present invention and the above-mentioned drawings are intended to cover non-exclusive inclusion. The terms "installed", "set", "provided with", "connected", "connected to", "socketed" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, or the internal connection between two devices, components or parts. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0042] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "one end", "the other end", "outer side", "inner side", "horizontal", "end", "length", "outer end", "left", "right", "up", "down", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. The terms "first" and "second" are also used only for the sake of simplicity in description, and do not indicate or imply relative importance.

[0043] ​

Claims

1. A voltage gain scalable Boost converter applicable to photovoltaic power generation, characterized in that: The converter includes a DC input source u in , a basic Boost converter, and n expansion units, where n is a natural number and the value range is n≥1; among them: The basic Boost converter includes an inductor L1, a power switch S1, a capacitor C1, and a diode D1; their connection form is as follows: the left end of the inductor L1 is connected to the positive pole of the DC input source, the right end of the inductor L1 is connected to the drain of the power switch S1, the source of the power switch S1 is connected to the negative pole of the DC input source, the gate of the power switch S1 is connected to the controller, the anode of the diode D1 is connected to the right end of the inductor L1, the cathode of the diode D1 is connected to the upper end of the capacitor C1, and the lower end of the capacitor C1 is connected to the source of the power switch S1 and the negative pole of the DC input source; The expansion unit includes two diodes and two capacitors; When n = 1, the first extended unit includes a first capacitor C 11 , a second capacitor C 12 , a first diode D 11 , a second diode D 12 ; wherein, the left end of the second capacitor C 12 of the first extended unit is connected to the anode of the diode D1 of the basic Boost converter, and the right end of the second capacitor C 12 is connected to the anode of the first diode D 11 and the cathode of the second diode D 12 , the anode of the second diode D 12 is connected to the cathode of the diode D1, the upper end of the first capacitor C 11 is connected to the cathode of the first diode D 11 , and the lower end of the first capacitor C 11 is connected to the anode of the second diode D 12 to form the first extended unit; When n = 2, the second capacitor C of the second extended unit 22 has its left end connected to the left end of the second capacitor C of the first extended unit 12 , the anode of the second diode D of the second extended unit 22 is connected to the cathode of the first diode D of the first extended unit 11 , the upper end of the first capacitor C of the second extended unit 21 is connected to the cathode of the first diode D of the first extended unit 11 . When n > 2, each extended unit is connected in sequence from bottom to top in this way until the left end of the second capacitor of the nth extended unit is connected to the left end of the second capacitor of the (n - 1)th extended unit, the anode of the second diode of the nth extended unit is connected to the cathode of the first diode of the (n - 1)th extended unit, and the upper end of the first capacitor of the nth extended unit is connected to the cathode of the first diode of the (n - 1)th extended unit; Both ends of the load R are respectively connected to the upper end of the first capacitor C in the nth expansion unit and the lower end of the capacitor C1 in the basic Boost converter. n1 and the lower end of the capacitor C1 in the basic Boost converter.

2. The voltage-gain expandable Boost converter applicable to photovoltaic power generation according to claim 1, wherein: When two expansion units are adopted, when the power switch S1 is turned on, the second diode D of the first expansion unit 12 and the second diode D of the second expansion unit 22 are turned on, the diode D1 of the basic Boost converter, the first diode D of the first expansion unit 11 , and the first diode D of the second expansion unit 21 are turned off, the input voltage u in is applied to the inductor L1, the current of the inductor L1 rises, the diode D1 of the basic Boost converter and the first diode D of the first expansion unit 11 and the first diode D of the second expansion unit 21 bear reverse voltage and are cut off, the second capacitor C of the first expansion unit 12 and the second capacitor C of the second expansion unit 22 are charged, and the capacitor C1 and the first capacitor C of the first expansion unit 11 and the first capacitor C of the second expansion unit 21 discharge to supply power to the load.

3. The voltage-gain expandable Boost converter applicable to photovoltaic power generation according to claim 1, wherein: When two expansion units are adopted, when the power switch S1 is turned off, the second diode D of the first expansion unit 12 , the second diode D of the second expansion unit 22 are turned off, the diode D1 of the basic Boost converter, the first diode D of the first expansion unit 11 , the first diode D of the second expansion unit 21 are turned on, the current of the inductor L1 decreases, and the input voltage u in , the inductor L1, the second capacitor C of the first expansion unit 12 and the second capacitor C of the second expansion unit 22 discharge, and the diode D1 of the basic Boost converter, the first diode D of the first expansion unit 11 and the first diode D of the second expansion unit 21 charge the capacitor C1 of the basic Boost converter and the second capacitor C of the first expansion unit 12 and the second capacitor C of the second expansion unit 22 while supplying power to the load.

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