TWI669983B - Led dimmer for plant growth - Google Patents

Abstract

An LED dimming device for plant growth, comprising: a step-up type returning conversion module, having a primary side circuit and having a high frequency switch, and a plurality of secondary side circuits and each having a low frequency switch; a plurality of LEDs having different illumination wavelength ranges required for plant growth are respectively disposed on the secondary circuit; the programmable control module is configured to drive the high frequency switch and the low frequency switch, and is allowed to be set according to writing. Changing the conduction rate of each low frequency switch to adjust the average current obtained by each LED distribution, and controlling the conduction rate of the high frequency switch to change correspondingly according to the difference between the on and off of each low frequency switch, so that each LED can be one during the conduction period. The average current (eg, the rated current value) of the predetermined value is driven; thereby, it can be driven by a low voltage DC source and provide individual dimming.

Description

LED dimming device for plant growth

The invention relates to an LED dimming device applied to plant growth, in particular to an LED dimming device which can be driven by a low voltage direct current such as a solar battery and allows individual dimming to be applied to plant growth.

Taiwan plant factories have gradually emerged in recent years. It is known from the literature that plants can be stimulated to grow by light source during the growth process. The possibility of replacing traditional fluorescent lamps with LEDs has been confirmed. LEDs are used as artificial light sources to shorten growth. The advantages of the period, the adjustment of the production period, the improvement of the quality or the increase of the output, and the LED itself has the characteristics of high luminous density and power saving, which can reduce the cost of electricity.

However, for different types of plants, or plants in different stages of growth, the required wavelength wavelength combinations and photoperiod conditions are not the same, as noted in the literature, such as 10A, 10B, and 10th. As shown in Figure C, it is indicated that the plant is most effective in the stage of seedling (Fig. 10A), and in the growth stage (Fig. 10B), the spectrum of blue-violet and red light is effective, while in the flowering stage. (Tenth C-picture) is most effective with red light spectrum. In order to meet the effective light irradiation required by plants, the use of LED-related dimming devices is required to provide the advantages of shortening the growth period, adjusting the production period, improving the quality or increasing the yield.

For the related case, there is the Republic of China New Patent Announcement No. M512289, "Light-emitting diode illumination structure suitable for multi-plant growth", which is a light-emitting diode illumination structure suitable for multi-plant growth. Indoor planting, including at least one circuit board, and the bottom surface of the circuit board is provided with a complex A plurality of diode groups such as white light, blue light and red light diodes can emit corresponding color light, and the distance between adjacent white light diodes is smaller than the distance between adjacent blue light or red light diodes, and the circuit board is transmitted through a The driving circuit is connected to a mode adjusting circuit and a time adjusting circuit, wherein the mode adjusting circuit enables the circuit board to illuminate only one of the diode groups, or simultaneously or sequentially illuminate all of them to form at least four illumination modes The time adjustment circuit can control the illumination and sleep time in each illumination mode to meet the photoperiod of different kinds of plants, and can effectively prevent white spot lesions of the leaves due to excessive illumination of blue light or red light.

However, the mode and time adjustment of the driving circuit of the foregoing method adjusts whether each of the light-emitting diodes is bright or not, to form a plurality of illumination modes, but the illumination result of the driving mode is relatively fixed and Restricted, it cannot be widely applied to different growth stages of different kinds of plants and plants, and the flexibility of use is insufficient.

Another example is the Republic of China Invention Patent Notice No. I574608 "Light Formula Verification Platform for Plant Factory", which has: a power converter to provide a variable output voltage; and an RGB LED circuit that controls red light by three drive signals. The average current of the LED, the green LED, and the blue LED; a photo sensor for providing red, green, and blue sensing signals; and a control unit for performing a driving signal generation program to The sensing signals of red, green, and blue light adjust the duration of the three driving signals to cause the RGB LED circuit to provide a desired light recipe, wherein the driving signal generating program is based on red LEDs, green light The comparison of the average current of the LED and the blue LED with a threshold current determines whether to operate in a first mode or a second mode.

However, the foregoing case is based on the sensing signal provided by the photo sensor to adjust the driving signals of the red LED, the green LED, and the blue LED to depend on the average current and threshold of the red LED, the green LED, and the blue LED. The comparison result of the current determines the working mode of the light formula, and the method of driving control of each LED is complicated, and the former case is used to overcome the compensation mechanism of the optical wavelength feedback The problem of shifting the wavelength of illumination light due to LED aging is not to control the LED illumination parameters depending on the type of plant, the stage of plant growth, etc., that is, there is currently no plant species or plant growth stage. A practical way to adjust LED lighting parameters differently.

Another example is the "Intelligent System for Regulating Indoor Plant Growth Environment and Its Control Method", which is an intelligent system for regulating the growth environment of indoor plants. It is characterized by: it includes a microcontroller, an analog temperature sensor, as described in the Chinese Patent Publication No. CN104932435A. , soil moisture sensor, LED lamp bead, low-voltage electric heating wire, ambient light sensor, RGB lamp bead, digital temperature sensor and SD card reader, the invention can effectively fix carbon dioxide in the air and release oxygen, compared with The traditional method of placing plants indoors without adjusting their state and physiological activities can effectively purify the indoor air environment and ensure the maintenance of physiological activities in a low illumination environment and a low root temperature environment. At a higher level, not only will not release more carbon dioxide, but also promote its ability to adsorb harmful gases, control plants to absorb harmful gases such as formaldehyde in the room, and purify the indoor air environment.

Among them, the above case discloses the use of electronic erasing rewritable read-only memory (EEPROM) for data storage, for providing 1024 storage bits capable of storing 0~255 digits, the address is 0-1023, respectively, for storing indoor temperature , soil temperature, soil moisture, data cache for storing short-cycle data, and power-down protection data area for recording current system status. However, the former case is used to adjust the growth environment parameters according to the growth environment of the plant, and is not used to adjust the growth environment parameters according to the plant species, growth stage, etc., and adjust the LED according to different plant species and different plant growth stages. Lighting parameters, the previous case also did not provide a practical control.

In addition, in order to comply with the relevant safety regulations, and to drive multiple sets of blue, green, red light of the three primary colors of the LED, the conventional circuit uses a flyback converter (Flyback Converter), through the coupled inductor Designed with multiple secondary windings, it can drive multiple LEDs with different rated voltage values and rated current values at the same time, and meet the safety regulations of electrical isolation.

However, due to the different types or stages of plants, the required wavelength combination and photoperiod are not the same. The secondary side circuit (13b) of the conventional flyback converter includes a diode switch (134b) as shown in FIG. 11 when the energy of the primary side of the converter is converted to the secondary side circuit (13b). The energy of all secondary sides can only be increased or decreased at the same time, so that individual dimming is not easy, and it is impossible to match the needs of plant growth to modulate LEDs of different luminous wavelengths.

Moreover, the driving circuit of the existing LED light source is mostly driven by the analog circuit IC (3b), and the dimming needs manual adjustment. If used for a plant rack, when different layers are placed on each layer, or the same species at different growth stages For plants, it is a huge cost for Agriculture 4.0 to measure and adjust the different combinations of light sources by hand.

In addition, the recent development of solar power generation in China has achieved considerable results. For example, the total solar power generation in the year of 105 has reached 1 billion degrees. This shows that the “special power policy” promoted by the government is quite successful. However, the promotion of solar power requires a considerable area of land. Therefore, the installation of solar panels on the agricultural land will make the plants on the original soil unable to be irradiated without the light source. It is known from the foregoing that the LED light source can provide various benefits to the plant by the effective wavelength. However, when solar power is used as the power source for driving the LED, the output voltage is lower due to the solar panel and the general green energy source. It is not easy to drive the LED light board well, nor can it be used in the conventional circuit as shown in Fig. 11. Therefore, there is a need to create a LED dimming device for plant growth that can be driven by a low voltage DC source.

Accordingly, in order to improve the above-mentioned deficiencies, the present inventors have made efforts to study and propose the LED dimming device for plant growth of the present invention, which can be driven by a low voltage DC source. The LED dimming device for plant growth comprises: a boost type flyback conversion module, comprising a coupled inductor, a primary side circuit and a plurality of secondary side circuits; the coupled inductor comprises a primary side winding And a plurality of secondary windings; the primary side circuit corresponds to the primary winding, and includes a high frequency switch, the primary side circuit is configured to connect to the low voltage DC source; and the secondary side circuit respectively corresponds to the secondary winding And each includes a low frequency switch; a plurality of LEDs each having a different wavelength range of wavelengths required for plant growth, and respectively disposed on the secondary circuit; a programmable control module electrically connecting the high frequency switch and the aforementioned low frequency a switch for driving the high frequency switch and the low frequency switch; the programmable control module is configured to control a change in a duty ratio of each of the low frequency switches according to a write setting to redistribute an average current obtained by each LED And allow the setting of the writing, according to the difference between the on and off of each low frequency switch, the conduction rate of the high frequency switch is controlled accordingly, so that the LEDs are guided The average current flowing during Jieneng meet a predetermined value.

Further, the predetermined value is the respective rated current of the LEDs used.

Further, the low voltage DC source is a solar battery pack.

Further, the programmable control module allows the high frequency switch and the low frequency switch to be simultaneously driven according to a predetermined time period according to a preset, and simultaneously does not drive the high frequency switch and the low frequency switch, and is used for The aforementioned LEDs are controlled to provide plant illumination in a suitable illumination cycle.

Further, the programmable control module includes a programmable module control board and an isolated integrated circuit. The programmable module control board is electrically connected to the isolation IC, and the isolation IC provides a high frequency switch connection pin and a plurality of The low frequency switch connecting pins are respectively electrically connected to the high frequency circuit switch and the low frequency circuit switch; the programmable module control board is configured to drive the high frequency switch and the low frequency switch, wherein the programmable module The control panel allows different control modes to be set to cause the aforementioned conduction rate to be changed correspondingly when the high frequency switch and the low frequency switch are driven in different control modes.

Further, the programmable control module further includes a display interface and an input interface, wherein the display interface and the input interface are electrically connected to the programmable module control board, and the input interface is configured to write the code of the control mode. The programmable module control board controls the programmable module to change its control mode, and the display interface includes a code for displaying the aforementioned control mode.

Further, the programmable control module generates a high frequency driving signal and a plurality of low frequency driving signals by using a pulse width modulation technology, respectively for driving the high frequency switch and the low frequency switch, by which the high frequency can be modulated The pulse width of each of the driving signal and the aforementioned low frequency driving signal is used to change the aforementioned conduction rate.

Further, the conductivity of the high-frequency power switch is changed according to the following formula: , , Wherein, L _p for the primary winding of the inductance value, V _in for the primary side circuit of the input voltage, D _H is turned for switching of the high-frequency circuit, P _o is the output power of the load, f _s is the high frequency driving The frequency of the signal, V _oi is the output voltage of each of the secondary circuits, L _Si is the inductance value of each of the secondary windings, L _{p is} the inductance of the primary winding, and n _i =N _p /N _Si is The primary side windings are each compared to the number of turns of the secondary winding.

Further, the secondary winding includes a first secondary winding, a second secondary winding, and a third secondary winding, and the secondary circuit includes a first secondary circuit and a second a secondary circuit and a third secondary circuit, the first secondary circuit includes a first diode, a second diode, and a first output capacitor, and the second secondary circuit includes a first a third diode, a fourth diode, and a second output capacitor, the third secondary circuit includes a fifth diode, a sixth diode, and a third output capacitor, and the low frequency switch includes a first low frequency switch, a second low frequency switch and a third low frequency switch, wherein the LED comprises a first wavelength LED, a second wavelength LED and a third wavelength An LED is connected to one end of the first secondary winding, and the other end of the first low frequency switch is connected to the anode end of the first diode, and the cathode end of the first diode is connected to the first output One end of the capacitor, the other end of the first output capacitor is connected to the other end of the first secondary winding, the second diode is connected to the end of the first output capacitor with a cathode end, and the first output capacitor is connected with an anode end The other end of the first output capacitor is connected to the positive terminal of the low voltage DC source, and the anode end of the first wavelength LED is connected to the end of the first output capacitor, and the first wavelength LED is negative. Extremely connecting the negative terminal of the low voltage DC source; one end of the second low frequency switch is connected to one end of the second secondary winding, and the other end of the second low frequency switch is connected to the anode end of the third diode, the third diode The cathode end is connected to one end of the second output capacitor, the other end of the second output capacitor is connected to the other end of the second secondary winding, and the fourth diode is connected to the end of the second output capacitor with a cathode end, and The anode end is connected to the second The other end of the output capacitor is connected to the positive end of the low voltage DC source, and the anode end of the second wavelength LED is connected to the end of the second output capacitor, the second wavelength LED The cathode end is connected to the negative terminal of the low voltage DC source; one end of the third low frequency switch is connected to one end of the third secondary winding, and the other end of the third low frequency switch is connected to the anode end of the fifth diode, the fifth two a cathode end of the pole body is connected to one end of the third output capacitor, and the other end of the third output capacitor is connected to the other end of the third secondary side winding. The sixth diode body is connected to the end of the third output capacitor with a cathode end. The other end of the third output capacitor is connected to the other end of the third output capacitor, and the other end of the third output capacitor is connected to the positive terminal of the low voltage DC source, and the anode end of the third wavelength LED is connected to the third output capacitor. At the end, the cathode end of the third wavelength LED is connected to the negative terminal of the low voltage DC source.

Further, the first wavelength LED is a series connection of at least one blue LED, the second wavelength LED is a series connection of at least one green LED, and the third wavelength LED is a series connection of at least one red LED.

According to the above technical features, the following effects can be achieved:

1. The primary side circuit of the step-up flyback conversion module is connected in series with the high frequency switch, and the low frequency switches of the relatively low frequency are connected in series in each secondary side circuit, and are redistributed by changing the conduction rate of each low frequency switch. The average current obtained by each LED is used to achieve the purpose of dimming, and at the same time, the conduction rate of the high-frequency switch is changed synchronously with the turn-on and turn-off of the low-frequency switches, so that each LED does not have a burning problem, and each The current flowing by the LED during its conduction can substantially conform to its rated current, and has better circuit utilization.

2. The circuit disclosed in the present invention can simultaneously boost the DC source and distribute energy to each LED according to the setting of each conductivity, and can drive the invention by a green energy source with a lower output voltage (such as a solar battery), and complete The purpose of dimming.

3. Combine the digital programmable control module with the required illumination of different growth stages of the plant, and write the corresponding control mode of each conduction rate into the programmable control module, thereby only changing the different control modes, ie The brightness of each LED can be changed, adjusted to the most effective illumination for plant growth, and the purpose of dimming is completed to make the plants grow better. The dimming process is simpler and faster than the analogy control. Save labor costs.

4. The programmable control module writes the corresponding code, and the high frequency switch and the low frequency switch are simultaneously driven or not driven according to a predetermined time period, and the programmable control module can be The aforementioned LEDs are controlled to provide the aforementioned effective illumination of the plants in a suitable illumination cycle.

5. The programmable control module uses a programmable module control board, and utilizes the programmable module control board to open the source code and the characteristics of the editable and memory program, allowing the general user to write various control modes for controlling the aforementioned conduction rate. , more flexible in use.

(1000)‧‧‧LED dimming device for plant growth

(1)‧‧‧Boost type flyback converter module

(111)‧‧‧ primary winding

(1121)‧‧‧First secondary winding

(1122)‧‧‧Second secondary winding

(1123)‧‧‧ Third secondary winding

(12) ‧‧‧primary circuit

(121)‧‧‧High frequency switch

(13) ‧‧‧secondary circuit

(131)‧‧‧First secondary circuit

(1311)‧‧‧First Diode

(1312)‧‧‧Secondary diode

(1313)‧‧‧First output capacitor

(1314)‧‧‧First low frequency switch

(132)‧‧‧Second secondary circuit

(1321)‧‧‧ Third Dipole

(1322) ‧ ‧ fourth diode

(1323)‧‧‧Second output capacitor

(1324)‧‧‧Second low frequency switch

(133)‧‧‧ Third secondary circuit

(1331)‧‧‧ Fifth Diode

(1332) ‧‧‧ sixth diode

(1333)‧‧‧ Third Output Capacitor

(1334)‧‧‧ Third low frequency switch

(2)‧‧‧LED

(21)‧‧‧First wavelength LED

(211)‧‧‧Blue LED

(22)‧‧‧second wavelength LED

(221)‧‧‧Green LED

(23)‧‧‧ Third wavelength LED

(231)‧‧‧Red LED

(3) ‧‧‧Programmable Control Module

(31)‧‧‧Programmable Module Control Board

(311), (311a) ‧ ‧ high frequency drive signal

(312), (312a)‧‧‧First low frequency drive signal

(313), (313a) ‧ ‧ second low frequency drive signal

(314), (314a)‧‧‧ Third low frequency drive signal

(32)‧‧‧Isolation IC

(321)‧‧‧High frequency switch connection pin

(322)‧‧‧The first low frequency switch connection pin

(323)‧‧‧Second low frequency switch connection pin

(324)‧‧‧ Third low frequency switch connection pin

(33)‧‧‧Input interface

(34)‧‧‧Display interface

(3b)‧‧‧ analog circuit IC

(13b) ‧‧‧secondary circuit

(134b)‧‧‧Diode Switch

(A) ‧‧‧Low voltage DC source

(B)‧‧‧Low frequency switch

(C)‧‧‧Low-frequency drive signal

[First Image] A circuit diagram of an LED dimming device applied to plant growth according to an embodiment of the present invention.

[Second diagram] is a circuit operation timing chart of an LED dimming device applied to plant growth according to an embodiment of the present invention.

[Third image] is a schematic diagram of a mode of operation of a circuit for an LED dimming device for plant growth according to an embodiment of the present invention.

[Fourth Diagram] is a schematic diagram of a second mode of operation of a circuit for an LED dimming device for plant growth according to an embodiment of the present invention.

[Fifth Figure] is a schematic diagram of a mode of operation of a circuit for an LED dimming device for plant growth according to an embodiment of the present invention.

[Sixth Diagram] is a schematic diagram of a mode operation mode of a circuit for applying a plant growth LED dimming device according to an embodiment of the present invention.

The seventh embodiment is used to describe the high frequency driving signal, the first low frequency driving signal, the second low frequency driving signal and the third low frequency driving signal output by the programmable module control board. Diagram of the relationship with current.

[Equation 8] In the control mode listed in the embodiment of the present invention, the high frequency driving signal, the first low frequency driving signal, the second low frequency driving signal, and the third low frequency driving signal and current are outputted. relation chart.

[Ninth aspect] is an analog circuit diagram for performing circuit simulation of electrical parameters listed in the embodiments of the present invention.

[Fig. 10A] A series of schematic diagrams of the required wavelength combinations of light at the seedling stage during plant growth.

[Fig. 10B] A series of schematic diagrams of the required wavelength combinations of light at the growth stage during plant growth.

[Tenth Cth] A series of schematic diagrams of the required wavelength combinations of light at the flowering stage during plant growth.

[11th] is a circuit diagram driven by a conventional flyback converter and analog circuit IC, indicating that individual dimming is not possible and is not suitable for low voltage DC source driving.

In combination with the above technical features, the main effects of the LED dimming device of the present invention applied to plant growth will be clearly shown in the following embodiments.

Please refer to the first figure, which is a LED dimming device (1000) for plant growth according to the embodiment, comprising a step-up type returning conversion module (1), a plurality of LEDs (2) and a Programming control module (3), wherein:

The step-up flyback conversion module (1) comprises a coupled inductor (not shown), a primary side circuit (12) and a plurality of secondary side circuits (13). Wherein, the coupled inductor comprises a set of primary side windings (111) and three sets of secondary side windings (not labeled), wherein the three sets of secondary side windings are respectively a first secondary side winding (1121), a first Two secondary windings (1122) and a third secondary winding (1123). The primary side circuit (12) corresponds to the primary side winding (111) and includes a high frequency switch (121) for turning on or off the primary side circuit (12). The primary side circuit (12) is connected to the first side circuit (12). Low voltage DC source (A). The second secondary circuit (13) has three groups, which are a first secondary circuit (131), a second secondary circuit (132), and a third secondary circuit (133), respectively. The first secondary winding (1121), the second secondary winding (1122), and the third secondary winding (1123), the secondary circuit (13) includes a low frequency switch (B), Used to turn on or off the respective secondary side circuits (13).

The foregoing LEDs (2) have three groups, which are respectively a first wavelength LED (21), a second wavelength LED (22) and a third wavelength LED (23), each having a different wavelength range of illumination required for plant growth, such as The blue light, the green light, and the red light are respectively disposed on the first secondary side circuit (131), the second secondary side circuit (132), and the third secondary side circuit (133).

Therefore, when the primary side circuit (12) is switched off, the low-voltage direct current source (A) is boost-converted, and the electric energy is distributed from the primary side winding (111) to the first two. a secondary winding (1121), the second secondary winding (1122), and the third secondary winding (1123), and the electric energy is distributed according to the first secondary circuit (131), the The second secondary side circuit (132) and the third secondary side circuit (133) are respectively connected to the low frequency switch (B), and the allocated electric energy is used to drive the first three LEDs (21), The second wavelength LED (22) and the third wavelength LED (23).

The programmable control module (3) is electrically connected to the high frequency switch (121) and the first low frequency switch (1314) for driving the high frequency switch (121) and the low frequency switch (B). By the means, the programmable control module (3) allows to control the respective duty ratio (Duty Ratio) of the low frequency switch (131) according to the setting of the write to redistribute the average current obtained by each LED (2); It is allowed to control the turn-on ratio (Duty Ratio) of the high-frequency switch (121) according to the setting of the write, in accordance with the difference between the on and off of each low-frequency switch (B), so that the LEDs (2) are The average current flowing during the on-time can meet a predetermined value, and the value is, for example, the respective rated current of the LEDs used.

Referring to the first figure, in detail, in the embodiment, the step-up type returning conversion module (1) is: the first secondary side circuit (131) and includes a first diode a body (1311), a second diode (1312) and a first output capacitor (1313), the second secondary circuit (132) and comprising a third diode (1321), a fourth two a pole body (1322) and a second output capacitor (1323), the third secondary circuit (133) and comprising a fifth diode (1331), a sixth diode (1332) and a third Output capacitor (1333), the low frequency switch (B) is a first low frequency switch (1314), a second low frequency switch (1324) and a third low frequency switch (1334).

Moreover, one end of the primary side winding (111) is connected to the positive end of the low voltage DC source (A), and the other end of the primary side winding (111) is connected to one end of the high frequency switch (121), and the other end of the high frequency switch (121) Connect the negative terminal of the low voltage DC source (A). One end of the first low frequency switch (1314) is connected to one end of the first secondary winding (1121), and the other end of the first low frequency switch (1314) is connected to the anode end of the first diode (1311), the first The cathode end of the diode (1311) is connected to one end of the first output capacitor (1313), and the other end of the first output capacitor (1313) is connected to the other end of the first secondary winding (1121), the second diode (1312) connecting the end of the first output capacitor (1313) with a cathode end and the other end of the first output capacitor (1313) with an anode end, the other end of the first output capacitor (1313) Connecting the positive terminal of the low voltage DC source (A), and the anode end of the first wavelength LED (21) is connected to the end of the first output capacitor (1313), and the cathode end of the first wavelength LED (21) is connected to the cathode terminal Low voltage DC source (A) negative terminal. One end of the second low frequency switch (1324) is connected to one end of the second secondary winding (1122), and the other end of the second low frequency switch (1324) is connected to the anode end of the third diode (1321), the third The cathode end of the diode (1321) is connected to one end of the second output capacitor (1323), and the other end of the second output capacitor (1323) is connected to the other end of the second secondary winding (1122), the fourth diode (1322) connecting the end of the second output capacitor (1323) with a cathode end, and connecting the other end of the second output capacitor (1323) with an anode terminal, the other end of the second output capacitor (1323) Connecting the positive terminal of the low voltage DC source (A), and the anode end of the second wavelength LED (22) is connected to the end of the second output capacitor (1323), and the cathode end of the second wavelength LED (22) is connected to the cathode terminal Low voltage DC source (A) negative terminal. One end of the third low frequency switch (1334) is connected to one end of the third secondary winding (1123), and the other end of the third low frequency switch (1334) is connected to the anode end of the fifth diode (1331), the fifth The cathode end of the diode (1334) is connected to one end of the third output capacitor (1333), and the third output capacitor (1333) The other end is connected to the other end of the third secondary winding (1123), the sixth diode (1332) is connected at the cathode end to the end of the third output capacitor (1333), and the anode end is connected to the third output. The other end of the capacitor (1333), the other end of the third output capacitor (1333) is connected to the positive terminal of the low voltage DC source (A), and the anode terminal of the third wavelength LED (23) is connected to the third terminal At the end of the output capacitor (1333), the cathode end of the third wavelength LED (23) is connected to the negative terminal of the low voltage DC source (A).

Also, in the present embodiment, a solar battery pack is used as the low voltage direct current source (A). The high frequency switch (121), the first low frequency switch (1314), the second low frequency switch (1324), and the third low frequency switch (1334) all use a metal oxide semiconductor field effect transistor. The programmable control module (3) uses a pulse width modulation technique to generate a high frequency driving signal, a first low frequency driving signal, a second low frequency driving signal and a third low frequency driving signal, respectively. Driving the high frequency switch (121), the first low frequency switch (1314), the second low frequency switch (1324), and the third low frequency switch (1334), by modulating the high frequency driving signal, the first The pulse width of each of the low frequency driving signal, the second low frequency driving signal and the third low frequency driving signal is used to change the conduction rate.

Preferably, in this embodiment, the programmable control module (3) includes a programmable module control board (31) and an isolated integrated circuit (hereinafter referred to as an isolation IC) (32). In this embodiment, The programmable module control board (31) is an Arduino control board. The programmable module control board (31) is electrically connected to the isolation IC (32). The isolation IC (32) provides a high frequency switch connection pin (321) and a first low frequency switch connection pin (322). a second low frequency switch connection pin (323) and a third low frequency switch connection pin (324) for electrically connecting to the high frequency switch (121), the first low frequency switch (1314), the first The low frequency switch (1324) and the third low frequency switch (1334) are configured for the programmable module control board (13) to transmit the generated high frequency driving signal, the first low frequency driving signal, the second low frequency driving signal and The third low frequency driving signal drives the high frequency switch (121), the first low frequency switch (1314), and the second low frequency switch (1324) and the third low frequency switch (1334). Wherein, using the programmable module control board (31) allows the user to preset or set a plurality of different control modes at any time to drive the high frequency switch (121) and the first low frequency switch in different control modes. (1314), the second low frequency switch (1324) and the third low frequency switch (1334), the aforementioned conduction rate is changed correspondingly.

Referring to the first figure and the second figure, wherein the second figure is a circuit operation timing diagram of the LED dimming device (1000) applied to the plant growth of the embodiment, because the first secondary circuit (131), The structure of the second secondary side circuit (132) and the third secondary side circuit (133) corresponds to each other, so that only the partial circuit is used in the following [ie, the primary side circuit (12) is matched with the first secondary side circuit ( 131)], to explain the circuit operation mode of the LED dimming device (1000) suitable for plant growth in the present embodiment, which is operable in the following four circuit operation modes:

Mode 1: Referring to the second diagram and the third diagram, when the high frequency switch (121) is at a positive potential, the high frequency switch (121) is turned on, and the voltage across the primary side winding (111) is V. _In , the current of the primary side winding (111) rises linearly, and the primary side winding (111) is in an energy storage state, at this time, due to the polarity of the first secondary winding (1121) and the primary winding (111) The opposite polarity, the first diode (1311) of the first secondary circuit (131) is reverse biased and not turned on, and the energy of the first wavelength LED (21) is from the previous cycle. The voltage VC1 of the first output capacitor (1313) charged and the input voltage V _in of the low voltage DC source (A) are provided.

Mode 2: Referring to the second and fourth figures, when the high frequency switch (121) is at a zero potential, the high frequency switch (121) is turned off, and the current i _{Lp of} the primary side winding (111) reaches a peak value. At this time, the current iLp of the primary side winding (111) instantaneously drops to zero. To maintain the magnetic flux balance, the first secondary side winding (1121) induces a first secondary side current i _S1 , and a part of the first The output capacitor (1313) is charged and the other portion supplies energy to the first wavelength LED (21).

Mode 3: Referring to the second and fifth figures, in the continuation mode 2, when the current of the first secondary side drops to zero, the circuit enters mode three, and the energy of the first wavelength LED (21) is The first output capacitor (1313) is provided.

Mode 4: Referring to the second and sixth figures, when the high frequency switch (121) and the first low frequency switch (1314) are both turned off, the first capacitor (1313) is not charged. a low voltage direct current source (A) of the input voltage V _in supplying energy via the second diode (1312) to the first wavelength LED (21), at which time the first wavelength LED (21) is cut into a voltage (the lowest brightness ).

The above operation mode illustrates that the driving of the LED (2) of the embodiment can be driven by at least the low voltage direct current source (A) with the cut-in voltage of the LED (2).

The dimming process of this embodiment will be described below:

Referring to the first and seventh figures, since the output voltage of green energy sources such as solar cells is generally low, the output voltage of a common solar battery pack is 12V, 24V, 48V, etc., and the solar battery pack of 48V is used in this embodiment. As the low voltage DC source (A). In the embodiment, the first wavelength LED (21) is connected in series with 20 blue LEDs (211), the total load voltage is 60V, the rated current is 0.34A, the total rated power is 20.4W, and the total cut-in voltage is 48V; The second wavelength LED (22) is connected in series with 20 green LEDs (221) with a total load voltage of 59V, a rated current of 0.35A, a total rated power of 20.6V, and a total cut-in voltage of 48V; the third wavelength LED ( 23) The series uses 28 red LEDs (231) in series with a total load voltage of 60V, a rated current of 0.47A, a total rated power of 28.2W, and a total cut-in voltage of 48V. It should be noted that since the red-light LED (231) has a low cut-in voltage, a large number of (28) red LEDs (231) are used in series to achieve a total cut-in voltage of 48V.

Referring to the first figure and the seventh figure, in use, the programmable module control board (31) outputs the high frequency driving signal (311), and controls the high frequency switch (121) to be turned on and off at a relatively high frequency. Switching, and outputting the first low frequency driving signal (312), the second low frequency driving signal (313) and the third low frequency driving signal (314), respectively controlling the low frequency switch (B) to be turned on and off at a relatively low frequency Inter-switching, so that the primary side current i _LP flows through the primary side winding (111) during each turn-on of the high frequency switch (121), and the secondary side that is turned on by the low frequency switch (B) each time it is turned off The winding (112) senses the secondary side current supply LED (2). In the configuration of the embodiment, the average value of the secondary current induced by the secondary winding (112) during any of the low frequency switches (B) is in compliance with the rated current of the LED (2). For example, during the conduction of the third low frequency switch (1334), the average value of the third secondary current induced by the third secondary winding (1123) is 0.48A. Therefore, when the pulse width of one of the aforementioned low frequency driving signals (C) is lowered, and the on time of one of the aforementioned low frequency switches (B) in one conducting period (ie, the turn-on conduction rate) is adjusted, the tone can be adjusted. Lowering the total average current finally obtained by one of the LEDs (2), and generating a lower luminance, such as the third low-frequency driving signal (314) in the seventh figure, so that the finally obtained red LED (231) is obtained. The total average current is the lowest. Similarly, the pulse width of one of the aforementioned low frequency driving signals (C) is raised, and the conduction time of one of the aforementioned low frequency switches (B) in one conduction period (ie, the conduction rate is adjusted) is raised. Corresponding to the total average current obtained by one of the LEDs (2), and generating a large illuminance, as in the seventh figure, the first low frequency driving signal (312) is raised to make the final blue LED (221) total. The average current is the highest.

Due to the configuration of the embodiment, if the first low frequency switch (1314), the second low frequency switch (1324), and the third low frequency switch (1334) are simultaneously turned on, the first secondary side circuit (131) The average current distributed by the second secondary circuit (132) and the third secondary circuit (133) can respectively conform to the first wavelength LED (21), the second wavelength LED (22), and the The rated current of the third wavelength LED (23), therefore, if any (or any) of the aforementioned low frequency switch (B) is switched to off first, the energy of the primary side current i _LP will be allotted to the rest The two (or one) of the aforementioned low frequency switch (B) corresponds to the secondary side circuit (13), which easily causes the remaining two (or one) LEDs (2) to burn out. Conversely, if the configuration of this embodiment is such that any one of the low frequency switches (B) (or any two) is turned on, the average current obtained by each of the low frequency switches (B) can be matched with the rated current of the LED (2), and then After the second (or another) low frequency switch (B) is also switched to be turned on, the three secondary circuits (13) are assigned an average current, which cannot meet the rated current, and cannot effectively utilize the circuit. Therefore, in this embodiment, in order to avoid the above situation, the three low-frequency switches (B) are respectively adjusted to be turned up or down in accordance with the respective on and off states, and the turn-on ratio of the high-frequency switch (121) is also synchronously adjusted. To synchronously increase or decrease the energy of the primary side current i _LP , for example, in conjunction with the seventh figure, the pulse width of the high frequency driving signal (311) in the interval t ₀ ' to t ₁ ' must be increased. The conduction rate of the high frequency switch (121) in the interval t ₀ ' to t ₁ ' is raised as D _H1 , and the energy i _LP of the primary side current is increased, and the circuit utilization is better, and when t ₁ In the interval 'to t ₂ ' and t ₂ ' to t ₃ ', the conduction rate of the high-frequency switch (121) must be lowered as D _H2 and D _H3 to reduce the energy i _{LP of} the primary current to avoid blue light. The LED (211) and the green LED (212) were burnt. In this embodiment, the programmable module control board (31) changes the respective conduction rates of the low frequency switches (B) according to different settings, and simultaneously changes the synchronous change of the conduction rate of the high frequency switches (121). . Further, in the present embodiment, the programmable module control panel (31) using the open source code allows the general user to preset according to the difference in planting plants and the stage of plant growth (or Multiple sets of different control modes are set at any time to control the change of the respective conduction rates of the low frequency switches (B) and the synchronous change of the conduction rate of the high frequency switches (A) in different control modes, thereby Adjusting the brightness of each of the first wavelength LED (21), the second wavelength LED (22), and the third wavelength LED (23) in the secondary circuit (13) in accordance with the plant demand, and maintaining the first The currents flowing by the one-wavelength LED (21), the second-wavelength LED (22) and the third-wavelength LED (23) during the conduction period thereof can substantially conform to the rated current thereof, and the LEDs (2) are not burned or The utilization of the circuit is insufficient.

Referring to the first and eighth figures, for example, the switching frequency of the first low frequency switch (1314), the second low frequency switch (1324), and the third low frequency switch (1334) are all 1 kHz, in one of the controls. The mode (such as the high frequency driving signal (311a) shown in the eighth figure, the first low frequency driving signal (312a), the second low frequency driving signal (313a) and the third low frequency driving signal (314a) are driven. The control mode of the first low frequency switch (1314) is 50%, the total average current output is 0.17A, the conduction rate of the second low frequency switch (1324) is 60%, and the total average current of the output For 0.21A, the third low frequency switch (1334) has a conduction ratio of 40%, and the total average current output is 0.19A, and can be adjusted to make the brightness of each LED (2) different. Referring to the following table (1), each low frequency switch (B) has a conduction mark of 1, and each low frequency switch (B) is marked with a cutoff of 0, and the switching frequency of the high frequency switch (121) is 32 kHz. During the switching period of a low frequency switch, there are six combinations of the conduction ratio of the high frequency switch (121), which are respectively t" ₀ ~ t" ₁ , t" ₁ ~ t" ₂ , t" _{2 in the} following table (1) ~ _H " ₃ , t" ₃ ~ t" ₄ , t" ₄ ~ t" ₅ and t" ₅ ~ t" ₆ corresponding to D _{H (C)} , D _{H (B)} , D _{H (A)} , D _H(E) , D _H(F) and D _H(H) .

Referring to the first figure, the circuit of the LED dimming device (1000) for plant growth in this embodiment operates in a discontinuous conduction mode (DCM), and the formula is known from the following formula (1), (2) and (3):

Wherein, L _p for the primary winding (111) of the inductance value, V _in for the primary side circuit (12) of the input voltage, D _H for the high-frequency switch (121) of the conducting ratio, P _o is the output power load , f _s is the frequency of the high frequency driving signal, V _oi is the respective output voltage of the secondary circuit (13), L _Si is the inductance value of each of the secondary windings (112), and L _{p is} the primary winding The inductance value of (111), n _i = N _p / N _{Si is} the turns ratio of the primary side winding (111) to each of the secondary windings (112).

The above-mentioned electrical specification values used in the present embodiment can be sorted into the following formula (II) by introducing the equations (1), (2) and (3).

And through the circuit simulation as shown in the seventh figure, the values of the respective conduction rates as shown in the following table (3) can be obtained:

The programmable control module (3) of the embodiment can be electrically connected to the programmable module control board (31) through an input interface (33) of a computer for writing the control of each of the above-mentioned conduction rates. The mode is on the programmable module control board (31), and the control mode corresponds to different stages of plant growth, such as a seedling stage, a growth stage, and a flowering stage, and the input interface (33) can be used to operate the programmable module. The control panel (31) switches its control mode to adjust the respective sets of LEDs (2) to a predetermined brightness requirement at a time, providing the most efficient illumination of plant growth. A display interface (34) of the computer is electrically connected to the programmable module control board (31), and can be used to display the code of the foregoing control mode or various parameters of the circuit of the embodiment.

In addition, the programmable module control board (31) can control the high frequency switch according to a predetermined time period by writing a corresponding code in the foregoing control mode as the input interface (33). The first low frequency switch (1314), the second low frequency switch (1324), and the third low frequency switch (1334) are simultaneously driven or not driven at the same time, whereby the programmable module control board (31) is The aforementioned LED (2) is controlled to provide the aforementioned effective illumination of the plant in a suitable illumination period, for example, to illuminate the plant for 16 hours with the aforementioned effective illumination every 24 hours, and the like.

In view of the foregoing description of the embodiments, the operation and the use of the present invention and the effects of the present invention are fully understood, but the above described embodiments are merely preferred embodiments of the present invention, and the invention may not be limited thereto. Included within the scope of the present invention are the scope of the present invention.

Claims (9)

An LED dimming device for plant growth can be driven by a low voltage DC source, comprising: a boost type flyback conversion module, comprising a coupled inductor, a primary side circuit and a plurality of secondary sides a circuit comprising: a primary side winding and a plurality of secondary side windings; the primary side circuit corresponding to the primary side winding and including a high frequency switch, the primary side circuit for connecting the low voltage DC source; The secondary side circuits respectively correspond to the secondary windings, and each comprises a low frequency switch; the plurality of LEDs each having different illumination wavelength ranges required for plant growth are respectively disposed on the secondary circuit; the programmable control module The high frequency switch and the low frequency switch are electrically connected to drive the high frequency switch and the low frequency switch; the programmable control module allows to control the respective turn-on ratios of the low frequency switches according to the setting of the writing. Change to re-allocate the average current obtained by each LED; and allow the high frequency switch to be controlled according to the setting of the write, in accordance with the difference between the on and off of each low frequency switch The flux rate is correspondingly changed so that the average current flowing by each LED during its conduction period can meet a predetermined value, and the programmable control module allows the timing to be simultaneously driven according to a predetermined time period according to the setting. The high frequency switch and the aforementioned low frequency switch, and simultaneously not driving the high frequency switch and the low frequency switch, are used to control the LED to provide plant illumination in a suitable illumination period. The LED dimming device for plant growth as described in claim 1, wherein the predetermined value is a respective rated current of the LEDs used. The LED dimming device for plant growth as described in claim 1, wherein the low voltage direct current source is a solar battery pack. The LED dimming device for plant growth as described in claim 1, wherein the programmable control module comprises a programmable module control board and an isolated integrated circuit, the programmable module control board Electrically connecting the isolated integrated circuit, the isolated integrated circuit provides a high frequency switch connecting pin and a plurality of low frequency switch connecting pins, respectively for electrically connecting to the high frequency circuit switch and the low frequency circuit switch; The programming module control board is configured to drive the high frequency switch and the low frequency switch, wherein the programmable module control board allows different control modes to be set to drive the high frequency switch and the low frequency switch in different control modes. Let the aforementioned conductivity change be correspondingly changed. The LED dimming device for plant growth according to the fourth aspect of the invention, wherein the programmable control module further comprises a display interface and an input interface, wherein the display interface and the input interface are electrically connected to the a programmable module control board, the input interface is configured to write the code of the foregoing control mode on the programmable module control board, and control the programmable module control board to change its control mode, and the display interface is configured to display the foregoing Control mode code. The LED dimming device for plant growth according to the first aspect of the invention, wherein the programmable control module generates a high frequency driving signal and a plurality of low frequency driving signals by using a pulse width modulation technique, respectively The high frequency switch and the low frequency switch are driven to change the conduction rate by modulating the pulse width of each of the high frequency driving signal and the low frequency driving signal. The LED dimming device for plant growth as described in claim 1, wherein the conductivity of the high frequency power switch is changed according to the following formula: , , Wherein, L _p for the primary winding of the inductance value, V _in for the primary side circuit of the input voltage, D _H is turned for switching of the high-frequency circuit, P _o is the output power of the load, f _s is the high frequency driving The frequency of the signal, V _oi is the output voltage of each of the secondary circuits, L _Si is the inductance value of each of the secondary windings, and n _i =N _p /N _{Si is} the primary winding and the secondary winding The odds ratio. The LED dimming device for plant growth according to claim 1, wherein the secondary winding comprises a first secondary winding, a second secondary winding, and a third secondary The winding, the secondary circuit includes a first secondary circuit, a second secondary circuit, and a third secondary circuit. The first secondary circuit includes a first diode and a second a diode and a first output capacitor, the second secondary circuit includes a third diode, a fourth diode, and a second output capacitor, the third secondary circuit includes a fifth The first low frequency switch, the second low frequency switch and the third low frequency switch, the LED includes a first wavelength LED and a second a wavelength LED and a third wavelength LED; one end of the first low frequency switch is connected to one end of the first secondary winding, and the other end of the first low frequency switch is connected to an anode end of the first diode, the first diode The cathode end is connected to one end of the first output capacitor, and the other end of the first output capacitor is connected Connected to the other end of the first secondary winding, the second diode is connected to the end of the first output capacitor with a cathode end, and the other end of the first output capacitor is connected with an anode end, the first output capacitor The other end is connected to the positive end of the low voltage DC source, and the anode end of the first wavelength LED is connected to the end of the first output capacitor, and the cathode end of the first wavelength LED is connected to the negative end of the low voltage DC source; One end of the second low frequency switch is connected to one end of the second secondary winding, the other end of the second low frequency switch is connected to the anode end of the third diode, and the cathode end of the third diode is connected to one end of the second output capacitor The other end of the second output capacitor is connected to the other end of the second secondary winding. The fourth diode is connected to the end of the second output capacitor with a cathode end, and the second output capacitor is connected with an anode end. The other end of the second output capacitor is connected to the positive end of the low voltage DC source, and the anode end of the second wavelength LED is connected to the end of the second output capacitor, and the cathode end of the second wavelength LED is connected. The low voltage DC source is negative One end of the third low frequency switch is connected to one end of the third secondary winding, the other end of the third low frequency switch is connected to the anode end of the fifth diode, and the cathode end of the fifth diode is connected to the third output One end of the capacitor, the other end of the third output capacitor is connected to the other end of the third secondary winding, the sixth diode is connected to the end of the third output capacitor with a cathode end, and the third output capacitor is connected with an anode end. The other end of the third output capacitor is connected to the positive terminal of the low voltage DC source, and the anode end of the third wavelength LED is connected to the end of the third output capacitor, and the third wavelength LED is negative. Extremely connected to the negative terminal of the low voltage DC source. The LED dimming device for plant growth according to claim 8, wherein the first wavelength LED is a series connection of at least one blue LED, and the second wavelength LED is at least one green LED connected in series. The third wavelength LED is connected in series with at least one red LED.