TWI836961B - Solar energy optimization device, solar energy generation system and power conversion system using the same - Google Patents

Abstract

A solar energy optimization device, a solar energy generation system and power conversion system using the same are provided. The solar energy optimization device includes a plurality of conversion circuits and a plurality of control circuits. Each of the conversion circuits is individually connected in series with a solar module. The conversion circuits and the solar modules are connected in series to a maximum power point tracking (MPPT) circuit. The MPPT circuit determines a photovoltaic current according to the solar modules. Each of the conversion circuits is used for converting a photovoltaic voltage of each of the solar module into an output voltage. Each of the control circuits is used to adjust a conversion parameter of each of the conversion circuits to increase each of the output voltages, so that under the same photovoltaic current, an output power of each of the solar modules is optimized.

Description

Solar power optimization device and solar power generation system using the same and power conversion systems

The present disclosure relates to a power optimization device and a power generation system and a power conversion system using the same, and in particular to a solar power optimization device and a solar power generation system and a power conversion system using the same.

Solar panels can convert solar energy into electricity and are a clean and environmentally friendly way of generating electricity. In order to reduce environmental pollution, solar power generation technology has been widely used in various buildings, ships or vehicles.

Because solar panels are constantly changing their current-voltage characteristic curves due to the influence of the environment, light, and other factors, in order to achieve better working efficiency, the maximum power point tracking (MPPT) technology is usually used to obtain the maximum power point.

The present disclosure relates to a solar power optimization device and a solar power generation system and power conversion system using the same, which uses a control circuit to modulate the conversion parameters of the conversion circuit to increase the output voltage, so that the output of each solar panel module The power is individually optimized to effectively increase the efficiency of the solar power generation system.

According to one aspect of the present disclosure, a solar power optimization device is provided. The solar power optimization device includes several conversion circuits and several control circuits. Each conversion circuit is individually connected in series to a solar panel module. These conversion circuits and these solar panel modules are connected in series to a maximum power point tracking circuit (MPPT circuit). The maximum power point tracking circuit determines a photovoltaic current based on these solar panel modules. Each conversion circuit is used to convert a photovoltaic voltage of each solar panel module into an output voltage. Each control circuit is used to adjust a conversion parameter of each conversion circuit to increase each output voltage, so that the output power of each solar panel module is optimized under the same photovoltaic current.

According to another aspect of the present disclosure, a solar power generation system is provided. The solar power generation system includes several solar panel modules, several conversion circuits, a maximum power point tracking circuit (MPPT circuit) and several control circuits. These conversion circuits are interconnected in series with these solar panel modules. These conversion circuits and these solar panel modules are connected in series to the maximum power point tracking circuit. The maximum power point tracking circuit determines a photovoltaic current based on these solar panel modules. Each conversion circuit is used to convert a photovoltaic voltage of each solar panel module into an output voltage. Each control circuit is used to adjust the relationship between each conversion circuit A conversion parameter is used to increase each output voltage so that the output power of each solar panel module is optimized under the same photovoltaic current.

According to another aspect of the present disclosure, a power conversion system is proposed. The power conversion system includes a first conversion device, a second conversion device and a maximum power point tracking circuit. The first conversion device has a first input terminal, a first conversion circuit, a first output terminal and a first control unit. The first input terminal is electrically connected to a first power source. The first conversion circuit is electrically connected to the first input terminal, the first output terminal and the first control unit. The second conversion device has a second input terminal, a second conversion circuit, a second output terminal and a second control unit. The second input terminal is electrically connected to a second power source. The second conversion circuit is electrically connected to the second input terminal, the second output terminal and the second control unit. The maximum power point tracking circuit is connected in series with the first output terminal and the second output terminal. The first control unit outputs a first control signal to adjust a first output voltage of the first conversion circuit, and the second control unit outputs a second control signal to adjust a second output voltage of the second conversion circuit.

In order to better understand the above and other aspects of this disclosure, the following is a specific example, and the attached drawings are used to explain in detail as follows:

100,300,900:Solar power generation system

110i, 310i: Solar panel module

120,220: Solar power optimization device

121i: conversion circuit

122i, 222i: control circuit

130,430,930: Maximum power point tracking circuit

400: Power conversion system

410: First conversion device

411: First conversion circuit

412: First control unit

420: Second conversion device

421: Second conversion circuit

422: Second control unit

911: First Power Source

912: Second power supply

C1: Capacitor

D1: Diode

E11: first input terminal

E12: First output terminal

E21: Second input terminal

E22: Second output terminal

I9: Photovoltaic current

L1: Inductor

Pi: Maximum power point

M11, M21: first control mode

M12, M22: Second control mode

PMi: Conversion parameters

S1: first control signal

S2: Second control signal

SLi, SLij: Solar panels

SW1: first switching element

SW2: Second switch element

V1: first output voltage

V1i, V3i: Photovoltaic voltage

V1i’, V3i’: output voltage

V2: second output voltage

Figure 1 is a schematic diagram of a solar power generation system according to an embodiment.

FIG. 2 shows a solar power generation system according to an embodiment.

Figure 3 illustrates a solar power optimization device and a solar panel according to an embodiment Circuit diagram of the module.

Figure 4 shows an example of how the control circuit adjusts the conversion parameters.

Figure 5 illustrates a circuit diagram of a solar power optimization device and a solar panel module according to another embodiment.

Figure 6 illustrates another way for the control circuit to adjust the conversion parameters.

Figure 7 illustrates a solar power generation system according to another embodiment.

FIG. 8 shows a power conversion system according to an embodiment.

Please refer to FIG. 1, which shows a schematic diagram of a solar power generation system 900 according to an embodiment. The solar power generation system 900 includes a plurality of solar panels SLi and a maximum power point tracking circuit (MPPT circuit) 930. The solar panels SLi are connected in series. The maximum power point tracking circuit 930 performs maximum power point tracking on all solar panels SLi to obtain the overall maximum power point and determine the photovoltaic current I9.

Due to differences in environment and aging, the power point of each solar panel SLi corresponding to the photovoltaic current I9 is not the maximum power point Pi of each solar panel SLi. This will make some solar panels SLi unable to achieve the best working efficiency.

Please refer to FIG. 2, which shows a solar power generation system 100 according to an embodiment. The solar power generation system 100 includes a plurality of solar panel modules 110i, a solar power optimization device 120, and a maximum power point tracking circuit 130. The solar panel modules 110i are connected in series. Each solar panel module 110i, for example, includes a solar panel or multiple solar panels. In the embodiment of FIG. 2, each solar panel module 110i includes only one solar panel SLi. The maximum power point tracking circuit 130 determines the overall maximum power point and photovoltaic current I9 based on these series-connected solar panel modules 110i.

In this embodiment, since the solar panel modules 110i are connected in series, the current flowing through each solar panel module 110i is the photovoltaic current I9.

The solar power optimization device 120 includes a plurality of conversion circuits 121i and a plurality of control circuits 122i. Each conversion circuit 121i is individually connected in series to the solar panel module 110i, and the conversion circuit 121i and the solar panel module 110i are alternately connected in series to the maximum power point tracking circuit 130.

Each conversion circuit 121i is used to convert the photovoltaic voltage V1i of each solar panel module 110i into an output voltage V1i'. The conversion circuit 121i is, for example, a buck converter circuit, a boost converter circuit, or a buck-boost converter circuit/FLYBACK converter circuit. The conversion circuit 121i has a rapid shunt down function, which can disconnect the solar panel module 110i when the system requires it.

Each control circuit 122i is connected to each conversion circuit 121i. Each control circuit 122i is used to adjust a conversion parameter PMi of each conversion circuit 121i. The conversion parameter PMi is, for example, a duty cycle or a duty frequency. When the conversion parameter PMi of the conversion circuit 121i is adjusted, the output voltage V1i' output by the conversion circuit 121i will also be modulated. Therefore, under the same photovoltaic current I9, the adjustment of the conversion parameter PMi can be used to increase each output voltage V1i', so that the output power of each solar panel module 110i is optimized.

Please refer to FIG. 3 , which illustrates a circuit diagram of the solar power optimization device 120 and the solar panel module 110i according to an embodiment. The conversion circuit 121i of the solar power optimization device 120 includes, for example, a first switching element SW1, a second switching element SW2, an inductor L1, a capacitor C1 and a diode D1. The control circuit 122i is connected to the output end of the inductor L1 to feed back the output voltage V1i' to the control circuit 122i, and the control circuit 122i detects changes in the output voltage V1i'. The control circuit 122i is further connected to the first switching element SW1 and the second switching element SW2 to control the first switching element SW1 and the second switching element SW2 according to changes in the output voltage V1i', thereby adjusting the conversion parameter PMi.

Please refer to Figure 4, which illustrates an example of how the control circuit 122i adjusts the conversion parameter PMi. In the first control mode M11, the control circuit 122i adjusts the conversion parameter PMi in a first direction. The first direction is, for example, to increase the value of the conversion parameter PMi. In the second control mode M12, the control circuit 122i adjusts the conversion parameter PMi in a second direction. The second direction is, for example, to reduce the value of the conversion parameter PMi.

After the first control mode M11 is executed, if the output voltage V1i' is pulled up, the first control mode M11 is continued to be executed (the control circuit 122i continues to adjust the conversion parameter PMi in the same first direction) so that the output voltage V1i' can continue to be pulled up. After the first control mode M11 is executed, if the output voltage V1i' is pulled down, it is changed to the second control mode M12 (the control circuit 122i adjusts the conversion parameter PMi in the opposite second direction) so that the output voltage V1i' can be pulled up.

After the second control mode M12 is executed, if the output voltage V1i' is pulled up, the second control mode is continued to be executed (the control circuit 122i continues to adjust the conversion parameter PMi in the same second direction) so that the output voltage V1i' can continue to be pulled up. After the second control mode M12 is executed, if the output voltage V1i' is pulled down, it is changed to the first control mode M11 (the control circuit 122i adjusts the conversion parameter PMi in the opposite first direction) so that the output voltage V1i' can be pulled up.

Each output voltage V1i' of each solar panel module 110i after optimization is not exactly the same. After each output voltage V1i' is increased, the output power of each solar panel module 110i is also increased, so that the overall output power can be significantly optimized.

In another embodiment, the control circuit 122i can also detect the photovoltaic voltage V1i and adjust the conversion parameter PMi accordingly. Please refer to FIG. 5 , which illustrates a circuit diagram of the solar power optimization device 220 and the solar panel module 110i according to another embodiment. The control circuit 222i of the solar power optimization device 220 is connected to the output end of the solar panel module 110i to feed back the photovoltaic voltage V1i to the control circuit 122i, and the control circuit 122i detects changes in the photovoltaic voltage V1i. The control circuit 222i is further connected to the first switching element SW1 and the second switching element SW2 to control the first switching element SW1 and the second switching element SW2 according to changes in the photovoltaic voltage V1i, thereby adjusting the conversion parameter PMi.

Please refer to FIG. 6 , which illustrates another way for the control circuit 222i to adjust the conversion parameter PMi. In the first control mode M21, the control circuit 222i adjusts the conversion parameter PMi in the first direction. The first direction is, for example, to increase the value of the conversion parameter PMi. in second In the control mode M22, the control circuit 222i adjusts the conversion parameter PMi in the second direction. The second direction is, for example, to reduce the value of the conversion parameter PMi.

After the first control mode M21 is executed, if the photovoltaic voltage V1i is pulled up, the first control mode M11 is continued (the control circuit 222i continues to adjust the conversion parameter PMi in the same first direction), so that the photovoltaic voltage V1i can continue to be pulled up. rise, thereby pulling up the output voltage V1i'. After the first control mode M21 is executed, if the photovoltaic voltage V1i is pulled down, it is changed to the second control mode M22 (the control circuit 222i adjusts the conversion parameter PMi in the opposite second direction) so that the photovoltaic voltage V1i can be pulled up. Then the output voltage V1i' is raised.

After the second control mode M22 is executed, if the photovoltaic voltage V1i is pulled up, the second control mode M22 is continued (the control circuit 222i continues to adjust the conversion parameter PMi in the same second direction), so that the photovoltaic voltage V1i can continue to be pulled up. rise, thereby pulling up the output voltage V1i'. After the second control mode M22 is executed, if the photovoltaic voltage V1i is pulled down, it is changed to the first control mode M21 (the control circuit 222i adjusts the conversion parameter PMi in the opposite first direction), so that the photovoltaic voltage V1i can be pulled up. Then the output voltage V1i' is raised.

After optimization, the output voltages V1i' of each solar panel module 110i are not exactly the same. After each output voltage V1i' is raised, the output power of each solar panel module 110i is also increased, so that the overall output power can be significantly optimized.

In addition, please refer to FIG. 7, which shows a solar power generation system 300 according to another embodiment. In the embodiment of FIG. 7, each solar panel module 310i includes a plurality of solar panels SLij. These solar panels SLij are connected in parallel to form the solar panel module 310i. Each conversion circuit 121i is used to convert the photovoltaic voltage V3i of each solar panel module 310i into an output voltage V3i'. Each control circuit 122i can adjust the conversion parameter PMi of each conversion circuit 121i to modulate the output voltage V3i' output by the conversion circuit 121i. Therefore, under the same photovoltaic current I9, the conversion parameter PMi can be adjusted to increase each output voltage V3i', so that the output power of each solar panel module 310i is optimized. In this embodiment, multiple solar panels SLij connected in parallel can be used as the optimization target, rather than a single solar panel SLij as the optimization target.

According to the above various embodiments, the control circuits 122i and 222i are used to modulate the conversion parameter PMi of the conversion circuit 121i to increase the output voltage V1i', so that the output power of each solar panel module 110i and 310i is individually optimized. Effectively improve the working efficiency of the solar power generation system 100, 300.

Furthermore, please refer to FIG. 8 , which illustrates a power conversion system 400 according to an embodiment. The technology of the present disclosure can also be implemented in the power conversion system 400. As shown in FIG. 8 , the power conversion system 400 includes a first conversion device 410 , a second conversion device 420 and a maximum power point tracking circuit 430 . The first conversion device 410 has a first input terminal E11, a first conversion circuit 411, a first output terminal E12 and a first control unit 412. The first conversion circuit 411 is, for example, the above-mentioned conversion circuit 121i. The first control unit 412 is, for example, the above-mentioned control circuits 122i and 222i. The first control unit 412 is, for example, the above-mentioned control circuit 122i. The first input terminal E11 is electrically connected to a first power supply 911. The first power supply 911 is, for example, the above-mentioned solar panel modules 110i and 310i. The first conversion circuit 411 is electrically connected to the first input terminal E11, the first output terminal E12 and the first control unit 412.

The second conversion device 420 has a second input terminal E21, a second conversion circuit 421, a second output terminal E22 and a second control unit 422. The second conversion circuit 421 is, for example, the above-mentioned conversion circuit 121i. The second control unit 422 is, for example, the above-mentioned control circuits 122i and 222i. The second input terminal E21 is electrically connected to a second power supply 912 . The second power supply 912 is, for example, the above-mentioned solar panel modules 110i and 310i. The second conversion circuit 421 is electrically connected to the second input terminal E21, the second output terminal E22 and the second control unit 422.

The maximum power point tracking circuit 430 is, for example, the above-mentioned maximum power point tracking circuit 130. The maximum power point tracking circuit 430 is connected in series with the first output terminal E12 and the second output terminal E22.

The first control unit 412 outputs a first control signal S1 to adjust a first output voltage V1 of the first conversion circuit 411. The first control signal S1 is, for example, a pulse width modulation signal. The first control unit 412 adjusts the first control signal S1 to change the voltage value of the first output voltage V1. For example, the first control unit 412 can adjust the duty cycle or frequency of the first control signal S1. The adjustment amplitude of the duty cycle or frequency of the first control signal S1 is, for example, 1% or a preset value. In one embodiment, the adjustment range of the duty cycle or frequency of the first control signal S1 can be dynamically adjusted instead of being a fixed value.

The first control unit 412 can measure changes in the first output voltage V1. When the voltage value of the first output voltage V1 decreases compared with the previously measured voltage value, the first control unit 412 can reversely adjust the duty cycle or frequency of the first control signal S1.

For example, when the voltage value of the first output voltage V1 increases correspondingly according to the increase of the duty cycle or frequency of the first control signal S1, the first control unit 411 continues to increase the duty cycle or frequency of the first control signal S1. When the voltage value of the first output voltage V1 decreases correspondingly according to the increase of the duty cycle or frequency of the first control signal S1, the first control unit 411 decreases the duty cycle or frequency of the first control signal S1.

The second control unit 422 outputs a second control signal S2 to adjust a second output voltage V2 of the second conversion circuit 421. The second control signal S2 is, for example, a pulse width modulation signal. The second control unit 422 adjusts the second control signal S2 to change the voltage value of the second output voltage V2. For example, the second control unit 422 can adjust the duty cycle or frequency of the second control signal S2. The adjustment amplitude of the duty cycle or frequency of the second control signal S2 is, for example, 1% or a preset value. In one embodiment, the adjustment amplitude of the duty cycle or frequency of the second control signal S2 can be dynamically adjusted rather than a fixed value.

The second control unit 422 can measure changes in the second output voltage V2. When the voltage value of the second output voltage V2 decreases compared with the previously measured voltage value, the second control unit 422 can reversely adjust the duty cycle or frequency of the second control signal S2.

For example, when the voltage value of the second output voltage V2 increases correspondingly according to the increase in the duty cycle or frequency of the second control signal S2, the second control unit 422 continues to increase the duty cycle or frequency of the second control signal S2. When the voltage value of the second output voltage V2 increases according to the duty cycle or frequency of the second control signal S2 When correspondingly decreasing, the second control unit 422 decreases the duty cycle or frequency of the second control signal S2.

In one embodiment, the voltage value of the first output voltage V1 and the voltage value of the second output voltage V2 may not be equal to each other.

According to the above embodiment, the first control unit 412 and the second control unit 422 are used to adjust the first control signal S1 and the second control signal S2 to increase the first output voltage V1 and the second output voltage V2, so that the output power of the first power source 911 and the second power source 912 can be optimized individually, effectively improving the working efficiency of the power conversion system 400. In other words, under the condition that the maximum power point tracking circuit 430 determines a photovoltaic current, the first control signal S1 and the second control signal S2 are adjusted to make the first output voltage V1 and the second output voltage V2 respectively become local maximum values, thereby maximizing the voltage sum of the first output voltage V1 and the second output voltage V2 to increase power.

In summary, although the present disclosure has been disclosed in the above embodiments, they are not used to limit the present disclosure. Those with ordinary knowledge in the technical field to which this disclosure belongs can make various modifications and modifications without departing from the spirit and scope of this disclosure. Therefore, the protection scope of the present disclosure shall be subject to the scope of the appended patent application.

100:Solar power generation system

110i:Solar panel module

120:Solar power optimization device

121i:Conversion circuit

122i: Control circuit

130: Maximum power point tracking circuit

I9: Photovoltaic current

PMi: conversion parameters

SLi: solar panel

V1i: photovoltaic voltage

V1i’: output voltage

Claims (16)

A solar power optimization device includes: a plurality of conversion circuits, each conversion circuit is individually connected in series to a solar panel module, and the conversion circuits and the solar panel modules are connected in series to a maximum power point tracking circuit (Maximum power point tracking circuit). point tracking circuit (MPPT circuit), the maximum power point tracking circuit determines a photovoltaic current based on the solar panel modules, and each conversion circuit is used to convert a photovoltaic voltage of each solar panel module into an output voltage; and A plurality of control circuits, each control circuit is used to adjust a conversion parameter of each conversion circuit to increase the output voltage, so that under the same photovoltaic current, an output power of each solar panel module is optimized , wherein each control circuit adjusts each conversion parameter in a first direction; if each photovoltaic voltage or each output voltage is pulled up, each control circuit continues to adjust each conversion parameter in the same first direction. ; If the photovoltaic voltage or the output voltage is pulled down, the control circuit continues to adjust the conversion parameters in a second opposite direction. A solar power optimization device as described in claim 1, wherein under the same photovoltaic current, the output voltages of the optimized solar panel modules are not completely the same. A solar power optimization device as described in claim 1, wherein one of the solar panel modules includes a plurality of solar panels connected in parallel. The solar power optimization device of claim 1, wherein one of the solar panel modules only includes one solar panel. A solar power optimization device as described in claim 1, wherein each conversion parameter is a duty cycle or a duty frequency. The solar power optimization device of claim 1, wherein each control circuit is connected to an output end of each conversion circuit to feed back the output voltage to each control circuit. The solar power optimization device of claim 1, wherein each control circuit is connected to an output end of each solar panel module to feed back each photovoltaic voltage to each control circuit. A solar power optimization device as described in claim 1, wherein each of the conversion circuits has a first switching element and a second switching element, and each of the control circuits is connected to each of the first switching element and each of the second switching elements to control each of the conversion circuits. A solar power generation system, including: a plurality of solar panel modules; a plurality of conversion circuits, the conversion circuits being alternately connected in series to the solar panel modules; A maximum power point tracking circuit (MPPT circuit). The conversion circuits and the solar panel modules are connected in series to the maximum power point tracking circuit. The maximum power point tracking circuit is based on the solar panel modules. The group determines a photovoltaic current, each conversion circuit is used to convert a photovoltaic voltage of each solar panel module into an output voltage; and a plurality of control circuits are used to adjust a conversion parameter of each conversion circuit. , to increase the output voltage, so that the output power of each solar panel module is optimized under the same photovoltaic current. A power conversion system includes: a first conversion device having a first input terminal, a first conversion circuit, a first output terminal and a first control unit, wherein the first input terminal is electrically connected to a first power source, and the first conversion circuit is electrically connected to the first input terminal, the first output terminal and the first control unit; a second conversion device having a second input terminal, a second conversion circuit, a second output terminal and a second control unit, wherein the second input terminal A second power source is electrically connected, the second conversion circuit is electrically connected to the second input terminal, the second output terminal and the second control unit; and a maximum power point tracking circuit is connected in series with the first output terminal and the second output terminal, wherein the first control unit outputs a first control signal to adjust a first output voltage of the first conversion circuit, and the second control unit outputs a second control signal to adjust a second output voltage of the second conversion circuit. A power conversion system as described in claim 10, wherein the voltage value of the first output voltage is not equal to the voltage value of the second output voltage. A power conversion system as described in claim 10, wherein the first control signal and the second control signal are pulse width modulation signals. The power conversion system of claim 10, wherein the first control unit adjusts the first control signal to change the voltage value of the first output voltage, and the second control unit adjusts the second control signal to change the voltage value of the first output voltage. 2. The voltage value of the output voltage. A power conversion system as described in claim 13, wherein the first control unit changes the duty cycle or frequency of the first control signal, and the second control unit changes the duty cycle or frequency of the second control signal. The power conversion system of claim 14, wherein when the voltage value of the first output voltage increases correspondingly according to the increase in the duty cycle or frequency of the first control signal, the first control unit continues to increase the first The duty cycle or frequency of the control signal; when the voltage value of the first output voltage decreases correspondingly according to the increase in the duty cycle or frequency of the first control signal, the first control unit reduces the duty cycle of the first control signal or frequency. A power conversion system as described in claim 14, wherein when the voltage value of the second output voltage increases correspondingly according to the increase of the duty cycle or frequency of the second control signal, the second control unit continuously increases the duty cycle or frequency of the second control signal; when the voltage value of the second output voltage decreases correspondingly according to the increase of the duty cycle or frequency of the second control signal, the second control unit decreases the duty cycle or frequency of the second control signal.

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