ELECTRIC VEHICLE CHARGING SYSTEM CAPABLE OF GENERATING ELECTRICITY BY SOLAR ENERGY

Abstract

An electric vehicle charging system capable of generating electricity by solar energy comprises a fixed solar panel (1) fixed on a roof, a movable solar panel (2), a solar panel state control device (3) and an intelligent voltage conversion and control module (4). The solar panel state control device is connected to the intelligent voltage conversion and control module, and controls stretched and contracted states of the movable solar panel, output voltages of the solar panel fixed on the roof and the movable solar panel are connected in parallel, and then are connected to the intelligent voltage conversion and control module, and the intelligent voltage conversion and control module controls the solar panel to generate a maximum conversion rate and a maximum charging power under different light intensities in different time periods, realizes docking with the electric vehicle, and controls charging.

Claims

1. An electric vehicle charging system capable of generating electricity by solar energy, comprising a fixed solar panel (1), a movable solar panel (2), a solar panel state control device (3), and an intelligent voltage conversion and control module (4), wherein the fixed solar panel (1) is fixedly mounted on a roof, the movable solar panel (2) is mounted on two sides of the fixed solar panel (1), and the solar panel state control device (3) is connected to the intelligent voltage conversion and control module (4), is used for receiving a vehicle-mounted signal and a signal of the intelligent voltage conversion and control module (4), and controls a stretched or contracted state of the movable solar panel (2), output voltages of the fixed solar panel (1) and the movable solar panel (2) are connected in parallel, and the output voltage obtained by the parallel connection is connected to the intelligent voltage conversion and control module (4), a voltage output terminal of the intelligent voltage conversion and control module (4) is connected to a charging port of the electric vehicle or a power battery of the electric vehicle, and the intelligent voltage conversion and control module (4) is used for controlling the solar panel to generate a maximum conversion rate and a maximum charging power under different light intensities in different time periods, is docked with the electric vehicle and controls charging, and monitors a charging process; wherein, the intelligent voltage conversion and control module (4) comprises a MCU intelligent computing controller (41), a current inductor (42), a voltage value detection circuit (43), a voltage converter (44) and a charging controller (45), the current inductor (42) and the voltage value detection circuit (43) respectively detect a charging current and a charging voltage, and are connected to the MCU intelligent computing controller (41), the MCU intelligent computing controller (41) is connected to the voltage converter (44), an output of the voltage converter (44) is linked with the charging controller (45), and the MCU intelligent computing controller (41) controls the voltage converter (44) to convert and generate different voltages under the same light intensity in the same time period, calculates and memorizes different charging powers and parameters according to a voltage and a current passed pack, selects a parameter corresponding to the maximum power to control an output voltage of the voltage converter (44), and charges the electric vehicle through the charging controller (45); the charging controller (45) is a charging controller (45) having handshake communication and control functions according to an interface standard of an original vehicle charging socket, an input terminal of the charging controller (45) is connected to an output terminal of the voltage converter (44), and an output terminal of the charging controller (45) is connected to an original DC charging port (51) of the electric vehicle, or is connected to a cathode or an anode of a power battery (53), or is connected to an alternating current charging port (54) of the electric vehicle to charge the electric vehicle; and the charging controller (45) is also connected to the MCU intelligent computing controller (41), and the MCU intelligent computing controller (41) controls the charging controller (45) to start or stop charging.

2. The electric vehicle charging system capable of generating electricity by solar energy according to claim 1, wherein the voltage converter (44) is a controllable DC/DC voltage converter (440) or DC/AC voltage converter (441), is controlled by the MCU intelligent computing controller (41), and is capable of outputting a continuously adjustable voltage.

3. The electric vehicle charging system capable of generating electricity by solar energy according to claim 1, wherein the solar panel state control device (3) comprises a driving structure (31) driving the movable solar panel to stretch, contract and translate, a driving control module (30) and a low-voltage 12-v rechargeable battery (32), the driving structure (31) is connected to the driving control module (30), the driving structure (31) is mounted at a bottom portion of the fixed solar panel (1), and the 12-v rechargeable battery (32) is connected to the driving control module (30) and the intelligent voltage conversion and control module (4) respectively, and provides a power supply needed for working.

4. The electric vehicle charging system capable of generating electricity by solar energy according to claim 3, wherein the driving control module (30) comprises a vehicle-mounted signal input unit (302), a MCU controller (301) and a motor controller (303), the MCU controller (301) is connected to the vehicle-mounted signal input unit (302), and is used for receiving a signal instruction of the vehicle related to charging, the MCU controller (301) is connected to the MCU intelligent computing controller (41), and is used for receiving charging state information, and the motor controller (303) is connected to the MCU controller (301) and the driving structure (31) respectively.

5. The electric vehicle charging system capable of generating electricity by solar energy according to claim 3, wherein the driving structure (31) comprises a motor (311) provided with a gear, a trunking guide rail (313) and a transmission rack (312), the transmission rack (312) is fixed below the movable solar panel (2), the motor (311) is mounted at two ends of the fixed solar panel (1), and is meshed with the transmission rack (312) through the gear, and the motor rotates to drive the movable solar panel (2) to translate along the trunking guide rail (313).

6. The electric vehicle charging system capable of generating electricity by solar energy according to claim 1, wherein the movable solar panel (2) is divided into a front part and a rear part, each part is composed of a single-layer or multi-layer solar panel, and has a single-layer structure or a multi-layer superimposed structure, and voltage output terminals of the fixed solar panel (1) and the movable solar panel (2) are respectively connected with a diode in series to prevent a current from flowing backwardly.

7. The electric vehicle charging system capable of generating electricity by solar energy according to claim 1, wherein the solar panel state control device (3) is further added with a telescopic supporting rod (315), one end of the telescopic supporting rod (315) is fixed on the roof, the other end of the telescopic supporting rod is hinged with a bottom portion of the fixed solar panel (1), three telescopic supporting rods are provided, and are respectively connected to the motor controller (303), the motor controller (303) changes a height of a supporting point of the solar panel, and changes a planar angle of the solar panel by controlling the supporting rod to stretch and contract, so that the solar panel is nearly perpendicular to a solar ray.

Description

DESCRIPTION OF THE DRAWINGS

[0026] FIG. 1 is a schematic structural diagram of a first embodiment of the present invention.

[0027] FIG. 2 is a principle topology schematic diagram of the first embodiment of the present invention.

[0028] FIG. 3 is a schematic structural diagram of a second embodiment of the present invention.

[0029] FIG. 4 is a principle topology schematic diagram of the second embodiment of the present invention.

[0030] FIG. 5 is a schematic structural diagram of a third embodiment of the present invention.

[0031] FIG. 6 is a principle topology schematic diagram of the third embodiment of the present invention.

[0032] FIG. 7 and FIG. 8 are enlarged drawings of part A in FIG. 1, FIG. 3 and FIG. 5 of the present invention.

[0033] FIG. 9 is a schematic diagram of an installation structure of a telescopic supporting rod and a fixed solar panel in the present invention.

[0034] FIG. 10 is an enlarged and internal structure diagram of the telescopic supporting rod in the present invention.

[0035] FIG. 11, FIG. 12 and FIG. 13 are three schematic structural diagrams of the connection between a charging controller and a charging port of an electric vehicle.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0036] To make the objects, technical solutions, and advantages of the present invention clearer, the present invention will be further described hereinafter with reference to the accompanying drawings and embodiments.

[0037] As shown in FIG. 1, FIG. 2, FIG. 7, FIG. 9, FIG. 10 and FIG. 11, an electric vehicle charging system capable of generating electricity by solar energy according to a first embodiment of the present invention is provided, which comprises a fixed solar panel 1 fixed on a roof, a stretchable and retractable movable solar panel 2, a solar panel state control device 3, and an intelligent voltage conversion and control module 4. The fixed solar panel 1 is fixedly mounted on the roof, and the movable solar panel 2 is mounted on two sides of the fixed solar panel. The solar panel state control device 3 is connected to the intelligent voltage conversion and control module 4, is used for receiving a vehicle-mounted signal and a signal of the intelligent voltage conversion and control module 4, and controls a stretched or contracted state of the movable solar panel 2. Output voltages of the fixed solar panel 1 and the movable solar panel 2 are connected in parallel, and the output voltage obtained by the parallel connection is connected to a voltage converter 44 in the intelligent voltage conversion and control module 4. A voltage output terminal b of the intelligent voltage conversion and control module 4 is connected to a DC charging port of the electric vehicle. The intelligent voltage conversion and control module 4 is used for converting an output voltage of the solar panel into a voltage for charging a power battery under different light intensities in different time periods, and controlling the solar panel to generate a maximum conversion rate and a maximum charging power in real time, is docked with the electric vehicle and controls charging, and monitors a charging process.

[0038] With the above structure, a state of the movable solar panel 2 is controlled by the solar panel state control device 3, which can be used to expand a total illumination area of the solar panel. When the electric vehicle is not running, the intelligent voltage conversion and control module 4 calculates a maximum electricity generation power according to the timing, so as to intelligently judge light intensity information, and meanwhile, combined with a voltage of the power battery detected, comprehensive state information is sent to the MCU controller of the solar panel state control device. After receiving the information, the MCU controller comprehensively judges whether to extend the movable solar panel by combining vehicle state information transmitted by an on-vehicle information input unit. In case of illumination, when the vehicle is not running and the battery is not fully charged, the movable solar panel is controlled to extend to front and rear sides of the vehicle, expanding the illumination area, so as to increase the electricity generation area fundamentally and provide necessary basic conditions for charging to reach a practical level. When driving, the solar panel is retracted. In addition, on the basis of increasing the electricity generation area of the solar panel, the conversion rate and output power of the solar panel under the same illumination condition in a certain time period are greatly affected by the load, but not fixed. According to this characteristic, the present invention additionally comprises the intelligent voltage conversion and control module, which can control the solar panel to generate the maximum conversion rate and maximum charging power in real time under various light intensities in each time period set, so that the solar panel with the increased area can be excited and controlled in each time period to emit maximized electric energy, and make the charging further reach the practical level. Meanwhile, through the charging controller comprised in the intelligent voltage conversion and control module 4, the present invention realizes docking with the electric vehicle to charge the power battery 53, so that the electricity generation capacity and charging capacity are close to the daily electricity consumption of the vehicle. In actual production, the solar panel state control device and the intelligent voltage conversion and control module are mounted at a bottom portion of the fixed solar panel or under a front cover of the vehicle.

[0039] The present invention can enlarge the illumination area of the solar panel, control the solar panel to be in the state of maximum conversion rate and maximum electricity generation power, realize the effective connection with the electric vehicle, realize the maximum charging power to charge the power battery, make the charging capacity close to the daily electricity consumption, reach the practical level, and can contract the solar panel when using the vehicle, so as to keep the original shape of the vehicle to a great extent and keep the aesthetics.

[0040] Each structural part of the present invention will be described in detail hereinafter with reference to the first embodiment and the corresponding drawings, and the details are as follows: as shown in FIG. 1 and FIG. 2, in the embodiment of the electric vehicle charging system capable of generating electricity by solar energy, the solar panel state control device 3 comprises a driving structure 31 driving the movable solar panel to stretch, contract and translate, a driving control module 30 and a low-voltage 12-v rechargeable battery 32. The driving structure 31 is connected to the driving control module 30, and the driving structure 31 is mounted at a bottom portion of the fixed solar panel. The 12-v rechargeable battery 32 is connected to the driving control module 30 and the intelligent voltage conversion and control module 4 respectively, and provides a power supply needed for working.

[0041] With the above structure, the solar panel state control device 3 of the present invention controls the driving structure 31 through the internal driving control module 30, so that the driving structure drives the movable solar panel 2 to translate and extend, expanding the illumination area of the solar panel. During driving, the movable solar panel 2 is driven to be retracted and hidden under the fixed solar panel 1, so that the sightseeing shape and aesthetics of the vehicle are kept, and the normal use of the vehicle is not affected.

[0042] As shown in FIG. 1, in the electric vehicle charging system capable of generating electricity by solar energy, the driving structure 31 comprises a motor 311 provided with a gear, a trunking guide rail 313 and a transmission rack 312. The movable solar panel 2 is divided into a left part and a right part, as shown in the enlarged drawing of FIG. 7. The movable solar panel is a single-layer movable solar panel, and the trunking guide rail is mounted on both sides of the fixed solar panel. The transmission rack 312 is fixed below the next movable solar panel 2, and the motor 311 is mounted at two ends of the fixed solar panel 1, and is meshed with the transmission rack 312 through the gear 316. The motor rotates to drive the movable solar panel 2 to translate along the trunking guide rail 313, and drive the left and right movable solar panels to extend or contract back and forth to the vehicle.

[0043] With the above structure, the gear can be rotated by the driving motor of the present invention so as to drive the transmission rack 312, so that the driving structure 31 can drive the movable solar panel 2 to translate and expand, and the driving control module 30 can control an expansion state of the movable solar panel 2.

[0044] In the actual production process, the movable solar panel is composed of a single-layer or multi-layer movable solar panel, as shown in the enlarged drawing of FIG. 8. The left and right movable solar panels may be expanded to be composed of multi-layer movable solar panels, adopting a multi-layer superimposed structure. The trunking guide rail is mounted on both sides of each solar panel. The trunking guide rail of next solar panel is embedded in the trunking guide rail of the previous solar panel. One end of the outer movable solar panel is fixed on the inner movable solar panel. When the motor is fixed at two ends of each trunking guide rail, and when the motor rotates, the gear drives the transmission rack, thereby driving the movable solar panel of next layer to translate.

[0045] In the electric vehicle charging system capable of generating electricity by solar energy as shown in the topology diagram of FIG. 2, the driving control module 30 comprises a vehicle-mounted signal input unit 302, a MCU controller 301, and a motor controller 303. The MCU controller 301 is connected to the vehicle-mounted signal input unit 302, and is used for receiving a signal instruction of the vehicle related to charging. The MCU controller 301 is connected to the MCU intelligent computing controller 41, and is used for receiving charging state information. The motor controller 303 is connected to the MCU controller 301 and the driving structure 31 respectively. The MCU controller 301 receives the state information of the vehicle and artificial control information through the vehicle-mounted signal input unit 302, and comprehensively and intelligently judges whether to extend the movable solar panel according to the state of the vehicle, an artificial instruction, a light intensity and a battery voltage state by combining information containing the charging state transmitted by the MCU intelligent computing controller 41. When the conditions are met and the solar panel area needs to be expanded, the MCU controller 301 controls the motor controller 303 to control the motor in the driving structure to rotate, so as to drive the movable solar panel 2 to move forward and backward to expand the illumination area. When the vehicle needs to be used, or when it is required to fold the movable solar panel artificially, or when an external environment has poor illumination conditions, the movable solar panel 2 will be automatically retracted and hidden under the fixed solar panel 1. In this case, the fixed solar panel 1 can still receive illumination to generate electricity and continue to charge the power battery during the driving process. In actual use, a control mode or instruction information may be given artificially through a switch or a remote control, and transmitted to the MCU controller 301 through the vehicle-mounted signal input unit, so that the state of the solar panel can be forcibly controlled in a specific occasion or before the vehicle is used. In practical application, the vehicle-mounted signal input unit may comprise a wireless transceiver module, which is used for receiving remote control signals or mobile phone monitoring signals, and send all charging information to a remote control terminal.

[0046] In actual production, the 12-v rechargeable battery may be an original low-voltage 12-v rechargeable battery of the vehicle, or may be an independent 12-v maintenance-free lead-acid battery. The battery is placed under the roof capable of generating electricity. While the intelligent voltage conversion and control module 4 charges the power battery, an output voltage of 14 v is also output through the internal voltage converter 44 to charge the 12-v rechargeable battery 32. Alternatively, in actual production, a switching power supply may also be used to take electricity from a cathode and/or an anode of the power battery, reduce the high voltage to a 12-v power supply, and then supply electricity to the driving control module 30, and supply electricity to the intelligent voltage conversion and control module to provide the power supply needed for working.

[0047] In actual production and application, voltage output terminals of the solar panels are connected in series with a diode to prevent a current from flowing backwardly. The MCU controller 31 of the solar panel state control device 3 intelligently controls the state of the movable solar panel according to signal requirements of the vehicle-mounted signal input unit, a light intensity signal transmitted by the intelligent voltage conversion and control module, and a plurality of factors or instruction requirements such as that whether the power battery voltage is fully charged. In actual use, by giving instruction requirements to the vehicle-mounted signal input unit, it is possible to manually control the expansion or non-expansion of the solar panel, and to choose to control the expansion of the movable solar panels on two sides or choose to only expand the solar panels on one side.

[0048] The specific embodiments above illustrate how the solar panel state control device can flexibly and effectively expand the solar panel area on a limited vehicle body area, so as to increase the electricity generation area fundamentally. On the other hand, according to the characteristics of the solar panel, the output power of the solar panel that already expands the total area will be greatly changed by the load under the same area and the same light intensity, and the output power is not a fixed output power. Therefore, through intelligent control of voltage conversion and intelligent calculation, finding a maximum power point, controlling a real-time output according to the maximum power, and adding the corresponding charging controller to dock with a charging control circuit of the electric vehicle, so as to realize the safe charging, are the other two important factors for the charging to reach the practical level. The specific implementation modes are as follows.

[0049] In the electric vehicle charging system capable of generating electricity by solar energy as shown in the topology diagram of FIG. 2, the intelligent voltage conversion and control module 4 comprises a MCU intelligent computing controller 41, a current inductor 42, a voltage value detection circuit 43, a voltage converter 44 and a charging controller 45. The current inductor 42 and the voltage value detection circuit 43 respectively detect a charging current and a charging voltage, and are connected to the MCU intelligent computing controller 41. The MCU intelligent computing controller 41 is connected to the voltage converter 44, and an output of the voltage converter 44 is linked with the charging controller 45. The MCU intelligent computing controller 41 controls the voltage converter 44 to convert and generate different voltages under the same light intensity in the same time period, detects different charging currents and charging voltages through the current inductor and the voltage value detection circuit, calculates and memorizes different charging powers according to a calculation formula that the power P=U*I, and selects a voltage conversion parameter corresponding to the maximum power to output a charging voltage, charges the power battery 53 of the electric vehicle through the charging controller 45, and controls in real time to obtain the maximum conversion rate and the maximum charging power under the same light intensity in each time period.

[0050] With the above structure, the intelligent voltage conversion and control module 4 can calculate the strongest electricity generation power in a certain time period, so as to judge the light intensity and send a light intensity signal to the solar panel state control device 3, and on other hand, can control the internal voltage converter 44 in real time, calculate and memorize different parameters to obtain the actual charging power, find and select the parameter corresponding to the maximum power, and control the voltage converter 44 to convert and output a voltage corresponding to the maximum charging power, so as to excite and control the solar panel to be in an output state with the maximum electricity generation power.

[0051] In the electric vehicle charging system capable of generating electricity by solar energy as shown in the topology diagram of FIG. 2, the voltage converter 44 is a DC/DC voltage converter 440, which is a voltage converter controlled by the MCU intelligent computing controller 41, and is capable of outputting a continuously adjustable voltage. The charging controller 45 is a charging controller having handshake communication and control functions according to an interface standard of an original vehicle DC charging socket. The charging controller 45 is connected to the voltage converter 44, and an output terminal b of the charging controller 45 is used as a voltage output terminal b of the intelligent voltage conversion and control module 4. As shown in the structure of FIG. 2, the output terminal b is connected to an original DC charging port 51 of the electric vehicle to charge the electric vehicle. According to the principle structure of the first embodiment of the present invention, a controllable and adjustable DC/DC voltage converter 440 is used in the voltage converter, and a voltage output by the voltage converter 440 enters the charging controller 45. The charging controller 45 comprises the handshake communication and control functions according to the original vehicle DC charging interface standard. The output terminal b of the charging controller 45 is connected with the DC charging port 51 of the electric vehicle through the following connection way. Preferably, as shown in FIG. 11, the tail end of the output terminal b is plugged into the charging port of the vehicle body by using a plug, or alternatively, as shown in FIG. 12, the output terminal b is connected to a rear end line of the charging socket. In actual production and application, or as further shown in FIG. 13, at an initial design stage of the vehicle, the charging socket is derived from a sub-charging access port built into a in-vehicle charging control circuit, and the output terminal b is connected to the sub-charging access port, thus being connected to an in-vehicle DC charging control circuit module 52 and integrated into a whole. In all the above ways, the output voltage of the charging controller 45 can charge the power battery of the electric vehicle through the in-vehicle charging control circuit.

[0052] The charging controller 45 is also connected to the MCU intelligent computing controller 41, and has the function of preventing voltage overshoot through mutual communication control. In the specific production and application, if the charging controller 45 is connected to an internal circuit at a rear end of the charging port, the charging controller 45 may send notification information to the MCU intelligent computing controller 41 when detecting charging or artificial uncovering a protective cover of the charging port, and the MCU intelligent computing controller 41 may send an instruction to control the voltage converter 44 to stop inverting the voltage, and control the charging controller 45 to release the circuit connection with the charging port to prevent charging conflict. When the vehicle is fully charged, the charging controller 45 may notify the MCU intelligent computing controller 41 to stop solar electricity generation and charging. When the artificial external charging exits and the conditions are met, the connection with the internal circuit at the rear end of the charging port is restored, and the solar charging mode is restored.

[0053] The solar panel 1 fixed on the roof and the movable solar panel 2 may preferably combine the voltages obtained by electricity generation in parallel, and the obtained output voltage is connected and input to the voltage converter 44 of the intelligent voltage conversion and control module 4. An output voltage of the voltage converter 44 passes through the charging controller, and a voltage output terminal of the charging controller is used as the voltage output terminal b of the intelligent voltage conversion and control module 4 to charge the power battery 53 of the electric vehicle.

[0054] As shown in FIG. 9 and FIG. 10, in the electric vehicle charging system capable of generating electricity by solar energy, the solar panel state control device 3 may further be added with a telescopic supporting rod 315. One end of the telescopic supporting rod 315 is fixed on the roof, and the other end of the telescopic supporting rod is hinged with a bottom portion of the fixed solar panel 1. Three telescopic supporting rods 315 are provided, and form a triangular structure with fixed supporting points of the fixed solar panel. A supporting rod motor 120 and a screw rod 121 are arranged in the telescopic supporting rod 315, one end of the screw rod 121 is connected with the supporting rod motor 120, and the other end of the screw rod 121 is hinged with the bottom portion of the fixed solar panel 1. The supporting rod motor 120 is driven by the motor controller, and the fixed solar panel 1 is mounted on the roof through the telescopic supporting rod 315. After the above structure is adopted, the solar panel state control device controls the expansion and contraction of the supporting rods through the motor controller, adjusts heights of the three supporting rods, and adjusts the three supporting points to change a plane angle of the solar panel. Meanwhile, the intelligent voltage conversion and control module calculates different powers in real time, and stops changing the angle when the solar panel gets the maximum capacity. Indifferent set time periods, according to the above method, a surface of the solar panel is nearly perpendicular to the solar ray, and a larger and more effective illumination receiving area can be obtained under different ray angle directions.

[0055] The description of the above structures refers to the specific implementation of the first embodiment. As shown in the structural drawing of FIG. 3 and the principle topology diagram of FIG. 4, a second embodiment of the present invention is different from the first embodiment in that the voltage output terminal of the intelligent voltage conversion and control module is connected to the cathode and/or the cathode of the power battery of the electric vehicle. In the actual production and application, a principle structure of the embodiment shown in FIG. 4 is adopted. The charging controller 45 comprises an on off control function. A voltage output of the voltage converter 440 enters the charging controller 45, and a cathode and/or an anode in the output terminal b of the charging controller 45 is connected to the cathode and/or the anode of the power battery directly. As shown in FIG. 5 and FIG. 6, a third embodiment of the present invention is different from the first embodiment in that the voltage output terminal of the intelligent voltage conversion and control module 4 is connected to an AC charging port of the electric vehicle. During actual production and application, a principle structure of the embodiment shown in FIG. 6 is adopted. A DC/AC voltage converter 441 is used in the voltage converter, and the output voltage enters the charging controller 45. The charging controller 45 comprises the handshake communication and control functions according to the AC charging interface standard of the original vehicle. The output terminal b of the charging controller is connected with the AC charging port 54 of the electric vehicle, that is, the AC slow charging port. The connection mode is as follows: the structure shown in FIG. 11 and FIG. 12 is also adopted, or as shown in FIG. 13, the output terminal b is further connected to an in-vehicle AC charging control circuit module 55, and integrated into a whole. The charging controller and the connection mode are specifically customized and matched according to protocol standards and handshake control circuits of different electric vehicle manufacturers.

[0056] In actual production and application, the electric vehicle mentioned in the present invention comprises pure electric vehicles and gas-electric hybrid vehicles.

[0057] The descriptions above are merely preferable embodiments of the present invention, and it should be noted that those of ordinary skills in the art may make a plurality of improvements and decorations without departing from the technical principle of the present invention, and these improvements and decorations shall also be deemed as the protection scope of the present invention.