TWM408678U - Photovoltaic powered system - Google Patents

Description

Correction and replacement page on May 24, 100. V. New description: [New technical field] [0001] This creation is related to a solar photovoltaic power generation system, especially a solar photovoltaic power generation system operating in parallel with AC mains. [Prior Art] [0002] Since solar energy has the characteristics of no pollution, pollution-free, and inexhaustible, the application of solar energy has considerable potential for development. Due to the active research and development of solar cells in recent years, it has achieved considerable efficiency. Therefore, it has gradually received the attention of countries such as Europe, the United States, and Japan, and has formulated policies to encourage the application. [_Taiguang f system mainly generates photoelectric power by photoelectric conversion of solar panels.] Then, the DC power supply is converted into an AC power source via a power conditioner for load use or a bus that feeds the utility power is synchronized in parallel with the commercial power. Therefore, in terms of functions, small distributed power generation systems can be divided into the following three types: (1) stand-alone system, () grid-connecti〇n system, and (3) Mixed. Hybrid system. The stand-alone system refers to the solar photovoltaic system that is connected to other power sources. It can only be directly supplied to the load connected to the system. Therefore, this system is more suitable for use in remote areas or isolated islands in the sea: where there is electricity supply. All the electric power is loaded with wind or yang: in addition to providing power for the load, the solar energy can charge the excess energy battery; when the solar power is not enough to provide the power required for the negative cutting, it is provided by the battery. . The Parallel System of the Mains is the solar photovoltaic system in parallel with the power company's network, as long as the utility power can be delivered normally at any location. If the form number A0101 page 3/total 30 pages M408678 __, the replacement of the page on May 24, 100, the power generation of the solar energy system is greater than the load demand, then the excess power can be fed back to the mains, and vice versa. When the photovoltaic system generates less power than the load, the utility will supply insufficient parts. In addition, a hybrid system has been developed in response to the problem of unstable power quality. When the utility power supply is stopped, the solar photovoltaic system can be immediately isolated from the mains by using the battery pack to form an independent operation power supply to provide short-term power. When the mains supply resumes power supply, the solar photovoltaic system is restored in parallel with the mains, and the battery pack is also charged. Compared with stand-alone systems, mains parallel systems are most common because they are less expensive and easier to maintain than batteries. 4 [0004] The mains parallel solar photovoltaic system architecture can be divided into a single-stage architecture and a two-stage architecture. Please refer to the first figure A and the first figure B for the block diagram of the conventional single-stage solar power parallel system and the block diagram of the two-stage solar power parallel system. As shown in Figure A, the solar photovoltaic system is operated in parallel with an AC mains 50A. The solar photovoltaic power generation system mainly comprises a solar photovoltaic module 10A, an input filter capacitor 20A and a DC/AC converter 40A. The solar energy module 10A converts the light energy into electrical energy to provide a direct current output voltage Vpv and a direct current output current.

Ipv. The input filter capacitor 20A is electrically connected to the solar photovoltaic module 10A to provide energy storage, energy release and filtering for the energy conversion operation of the back end circuit. The DC/AC converter 40A is electrically connected to the input filter capacitor 20A, and can be converted into amplitude and frequency by means of a Sinusoidal Pulse-Width-Modulation (SPWM) method. Change the sine wave AC power, and can feed the bus to the mains and the AC mains 50A synchronization form number A0101 Page 4 / 30 pages i M408678 On May 24, 100, the replacement page was operated in parallel. The single-stage solar mains parallel system has the advantages of simple circuit, easy control and high efficiency, so it is suitable for high power, high solar photovoltaic output voltage. The disadvantage is that the solar photovoltaic module 10A directly connects the DC/AC converter 40 A high-voltage DC link (DC bus). For the application of the low-power system, the array combination is less flexible, and the battery serial connection method is used. High voltage short circuit danger and low reliability.

[0005] As shown in the first figure B, the architecture of the two-stage solar power parallel system is the same as the single-stage solar power parallel system. However, the biggest difference between the two is that the two-stage solar power parallel system further includes continuous current/ DC converter 30A. The DC/DC converter 30A is electrically connected to the input filter capacitor 20A to receive the filtered voltage output by the input filter capacitor 20A.

The voltage level of the DC power source is increased after filtering. As for the circuit function of the back end, it is the same as the single-stage solar power parallel system, so it will not be described again. The advantage of the two-stage solar utility parallel system architecture is that there is no need to connect a plurality of the solar photovoltaic modules 10A in series, which can reduce the volume and cost, and the combination of the modular array and the reliability of the connection is high. The disadvantage is that high-frequency switching combined with a two-stage circuit architecture is inefficient. [0006] The above-mentioned single-stage and two-stage solar power parallel system architectures both use the DC/AC converter 40A with high frequency switching, and the basic condition of the parallel connection with the AC mains 50A is the output amplitude (amplitude). The frequency and phase must be the same as the AC mains 50A. Before the solar power parallel system is connected in parallel with the AC mains 5 0 A, the converter must be synchronized with the AC mains 50A by a phase-locked-loop (PLL), and must have good current control performance, otherwise parallel The transient or parallel process will cause a circulating current that will cause damage to the converter. Form No. A0101 Page 5 of 30 M408678 _, May 24, 100 Nuclear Replacement Page In addition, the main disadvantage of the DC/AC converter 40A is that the innate current limiting characteristics are poor and the current control performance is susceptible to the DC link. The voltage influence of the AC mains 50A is easy to over-current during the parallel and load change transients. [0007] Therefore, how to design a solar photovoltaic power generation system, which can improve the shortcomings of the DC/AC converter 40A and improve the overall conversion efficiency to achieve high utilization rate of solar photovoltaic energy, is the creator of the present invention to overcome and A major issue to be solved. [New content]

[0008] In order to achieve the above object, the present invention provides a solar photovoltaic power generation system that provides a DC power supply through a solar photovoltaic module, and converts the DC power supply into an AC power source, and then operates in parallel with an AC power supply. The solar photovoltaic power generation system comprises the solar photovoltaic module, a coupling capacitor unit and an AC module. [0009] The coupling capacitor unit is electrically connected to the solar photovoltaic module to filter the DC power supply provided by the solar module. [0010] The AC module is electrically connected to the coupling capacitor unit to convert the filtered DC power source into a half sine wave current. The AC module includes an active clamping circuit, a power converter, and an AC selection switch circuit. [0011] The active clamping circuit has a first clamping switch, a second clamping switch, a first clamping capacitor and a second clamping capacitor, and receives the filtered DC power supply to reduce the filtering. The voltage surge of the DC power supply afterwards. The power converter is electrically connected to the active clamping circuit, has an isolation transformer, and the primary side of the isolation transformer has a first main opening form number A0101 page 6 / total 30 pages M408678 - May 24, 100 The Japanese core replaces the page and a second main switch, and the secondary side of the isolation transformer has a rectifier circuit composed of two diodes and two filter capacitors to receive the DC power source to convert the DC voltage of the DC power source. The level is regulated and the DC power source is rectified. The AC selection switch circuit is electrically connected to the power converter and the AC mains, and has a full bridge structure formed by a plurality of power switches, and is alternately switched in the AC mains synchronous mode.

[0012] Thereby, the half sine wave current is converted into a full sine wave current, and after filtering the high frequency switching component of the full sine wave current, the output current is made pure sinusoid and is in phase with the alternating current mains, The maximum power point tracking control and unit power of the solar photovoltaic module are fed into the AC mains. [0013] In order to achieve the above object, the present invention provides an AC module of a solar photovoltaic power generation system that receives a DC power source and converts the DC power source into an AC power source, and then operates in parallel with an AC power source. The AC module includes an active clamp circuit, a power converter, and an AC selection switch circuit. [0014] The active clamping circuit has a first clamp switch, a second clamp switch, a first clamp capacitor and a second clamp capacitor, and receives the DC power supply to reduce the voltage of the DC power supply. Surge. The power converter is electrically connected to the active clamping circuit, and has an isolation transformer, and the primary side of the isolation transformer has a first main switch and a second main switch, and the secondary side of the isolation transformer has two The rectifier circuit formed by the diode and the two filter capacitors receives the DC power source, converts the DC voltage level of the DC power source, and rectifies the DC power source. The AC selection switch circuit is electrically connected to the power converter and the AC mains, and has a full bridge structure formed by a plurality of power switches to exchange the city form number A0101. Page 7 of 30 M408678 100 May 24 The day correction replaces the page with the electronic synchronization mode interactive switching. [0015] Thereby, the half sine wave current is converted into a full sine wave current, and after filtering the high frequency switching component of the full sine wave current, the output current is made pure sinusoid and is in phase with the alternating current mains, The maximum power point tracking control and unit power of the solar photovoltaic module are fed into the AC mains. [0016] In order to further understand the techniques, means and effects of this creation in order to achieve the intended purpose, please refer to the following detailed description and drawings of the creation, and believe that the purpose, characteristics and characteristics of the creation can be obtained therefrom. The in-depth and specific understanding of the present invention is provided by way of illustration and description. [Embodiment] [0017] The technical content and detailed description of the present invention are as follows: [0018] Please refer to the second figure for a block diagram of the solar photovoltaic power generation system. The solar photovoltaic power generation system provides a DC power supply (including a DC output voltage Vpv and a DC output current Ipv) through a solar photovoltaic module 10, and converts the DC power source into an AC power source, and then is connected in parallel with an AC mains 40. Running. The solar photovoltaic power generation system includes the solar photovoltaic module 10, a coupling capacitor unit 20, and an AC module 30. [0019] The coupling capacitor unit 20 is electrically connected to the solar photovoltaic module 10 to filter the DC power supply provided by the solar photovoltaic module 10. The AC module 30 is electrically connected to the coupling capacitor unit 20 and adopts a continuous conduction mode (CCM) to convert the filtered DC power source into a half sine wave current. Where the form number A0101

Page 8 of 30 M408678 May 24, 2014 Pressing the Replacement Page The AC module 30 includes an active clamp circuit 302, a power converter 304, and an AC select switch circuit 306.

[0020] The solar photovoltaic power generation system further includes a line frequency switching switch 50, a maximum power tracking controller 60, a voltage/current detecting circuit 70, and a driving circuit 80. The line frequency switching switch 50 is electrically connected to the AC module 30, and receives the output voltage and current of the AC module 30 to generate driving signals for driving the power switches of the AC selection switch circuit 306. The voltage/current detecting circuit 70 is electrically connected to the solar photovoltaic module 10 and the coupling capacitor unit 20 to detect the DC output voltage Vpv of the solar photovoltaic module 10 and the DC output current Ipv, and A driving signal is generated for the first clamp switch 3022 and the second clamp switch 3024 of the active clamp circuit 302 and the first main switch 3042 and the second main switch 3044 of the power converter 304. The maximum power tracking controller 60 is electrically connected to the AC module 30 and the voltage/current detecting circuit 70, and uses the power outputted by the AC module 30 to calculate a maximum power tracking command signal to control the The voltage/current detection circuit 70 adjusts the voltage or current operating point of the solar photovoltaic module 10 to provide maximum power tracking control. The driving circuit 80 is electrically connected to the voltage/current detecting circuit 70, the line frequency switching switch 50, and the AC module 30, respectively receiving the voltage/current detecting circuit 70 and the line frequency switching switch 50. The driving signals are used to drive the active clamping circuit 302 of the AC module 30 and the AC selection switch circuit 306. [0021] Please refer to the circuit diagram of the first embodiment of the active clamp circuit of the present invention. As described above, the AC module 30 also includes an active clamping circuit 302, a power converter 304, and an AC selection form number A0101. Page 9/Total 30 pages M408678 ___ 100 years of May 24th revised replacement page Switch circuit 306 is selected. As shown in the third figure, the active clamp circuit 302 has a first clamp switch 3022, a second clamp switch 3024, a first clamp capacitor 3026, and a second clamp capacitor 3028. The active clamp circuit 302 receives the filtered DC power supply to reduce the voltage surge of the filtered DC power supply. The first clamp switch 3022 and the second clamp switch 3024 both include an anti-parallel diode (not labeled), or a body diode and a parasitic capacitance. (not shown). The power converter 304 is electrically connected to the active clamp circuit 302, has an isolation transformer (not labeled), and the primary side (not labeled) of the isolation transformer has a first < a main switch 3042 and a second main The switch 3044, the secondary side (not labeled) of the isolation transformer has a rectifying circuit composed of two diodes D1, D2 and two filter capacitors Cr 1, Cr2 to receive the DC power source and convert the DC power of the DC power source The voltage level is rectified and the DC power source is rectified. [0022] The power converter 304 is a current feed type push-pull converter

(current-fed push-pull converter) ° and the isolation transformer of the power converter 304 is a primary side center tap and a secondary side providing voltage doubler rectification to increase the output voltage level of the solar photovoltaic module 10 to The AC mains supply is 40 level, and the AC mains 40 can be fed into the current source type. In addition, the first clamp switch 3022 of the active clamp circuit 310 is complementary to the first main switch 3042 of the power converter 304, and the second clamp of the active clamp circuit 302 Switch 3024 is complementary to the second main switch 3044 of power converter 304. In addition, the first main switch 3042 of the power converter 304 is switched out of phase with the second main switch 3044 of the power converter 304. Form No. A0101 Page 0/Total 30 pages M408678 100 May On the 24th, the nuclear replacement page was replaced. Moreover, when the first clamp switch 3022 of the active clamp circuit 302 is switched with the first main switch 3042 of the power converter 304; and the second clamp switch 3024 of the active clamp circuit 302 and the When the second main switch 3044 of the power converter 304 is switched, a dead time is provided for soft switching.

[0023] The AC selection switch circuit 306 is electrically connected to the power converter 304 and the AC mains 40, and has a full bridge architecture (not labeled) formed by a plurality of power switches, and is alternately switched in the synchronous manner of the AC mains 40. Converting the half sine wave current into a full sine wave current, and filtering out the high frequency switching component of the full sine wave current, the output current is pure sinusoid and is in phase with the AC mains 40 to achieve the solar photovoltaic mode Group 10's maximum power point tracking control and unit power factor are fed into the AC mains 40. The power-on relationship of the AC selection switch circuit 306 is a metal-oxide-semiconductor field effect transistor (MOSFET).

[0024] The following describes the operation principle of the AC module 30, and understands the working principle and characteristics of the creation. The third picture is reviewed to reveal the circuit structure of the AC module 30 with a flexible switching push-pull solar photovoltaic system. According to the isolation transformer, it is divided into a low pressure side (primary side) and a high pressure side (secondary side). The low voltage side includes the first main switch 3042 and the second main switch 3044 of the power converter 304, and the first clamp switch 3022 and the second clamp switch 3024 of the active clamp circuit 302. A clamp capacitor 3026 and the second clamp capacitor 3028. The first clamp switch 3022 through the active clamp circuit 302 is complementary to the first main switch 3042 of the power converter 304, and the form number of the active clamp circuit 302 is A0101. Page 30, M408678, May 24, 2014, Nuclear Replacement Page, second clamp switch 3024 is complementary to the second main switch 3044 of the power converter 304, and the first main switch of the power converter 304 The 3042 is 180 degrees out of phase with the second main switch 3044 of the power converter 304. And using the first clamp switch 3022 and the anti-parallel diodes of the second clamp switch 3024 and the primary side leakage inductance (not shown) of the isolation transformer and the parasitic capacitance to provide a zero voltage flexible switching The energy needed to achieve a normal zero voltage switching operation. [0025] It is worth mentioning that, from the foregoing system description, since the AC selection switch circuit 306 only performs low frequency switching and has no current control capability itself, the electric < force converter 304 needs to be able to generate the half sinusoidal current. However, in order to generate the half sinusoidal current and consider the characteristics of the high boost ratio in parallel with the AC mains 40, an input inductor Lin is connected in series with the input end of the solar photovoltaic power generation system to realize the current source conversion benefit. And switching through the switch of the first clamp switch 3022, the second clamp switch 3024, the first main switch 3042 and the second main switch 3044 on the low voltage side of the isolation transformer to perform half sine modulation to operate In the continuous conduction mode, the isolation transformer adopts the primary center tap and the secondary side to provide multiple voltage rectification to increase the output voltage of the solar photovoltaic module 10 to the 'AC mains 40 level, and then The AC mains 40 can be fed in a current source version. Therefore, the AC module 30 of the solar photovoltaic power generation system can generate a continuous half sine wave current, and the back end is further switched through the AC selection switch circuit 306 in the synchronous manner of the AC main power 40, and the half sine wave current is converted. The sinusoidal current is obtained, and after filtering the capacitor to attenuate the high frequency switching component, the output current can be purely sinusoidal and in phase with the AC mains 40 voltage, so as to achieve the maximum power point tracking control of the solar photovoltaic module 10, single form number A0101 12 pages / a total of 30 pages M408678 On May 24, 100, Shuttle was replacing the page position for the purpose of feeding into the city. In addition, the active clamp circuit 302 of the solar photovoltaic power generation system can be mated with different circuit settings, and other embodiments of the inventive circuit architecture can be developed. Please refer to FIG. 4, FIG. 5 and FIG. 6 are circuit diagrams of a second embodiment, a third embodiment and a fourth embodiment of the active clamp circuit of the active AC module, respectively. The second embodiment and the third embodiment are only for the connection of the first clamp switch 3022, the second clamp switch 3024, the first clamp capacitor 3026, and the second clamp capacitor 3028. The first embodiment is different, and the fourth embodiment is used in conjunction with the first clamp switch 3022 and the second clamp switch 3024 as a clamp capacitor Cc, and the operation principle thereof is the same, and thus will not be described again. [0027] In addition to the above-described AC clamp module 30, the active clamp circuit 302 has different implementations.

In addition to the aspect, the creation further provides that the communication module 30 has different implementation aspects. Please refer to the seventh figure for a circuit diagram of another embodiment of the AC module of the present invention, and the AC module 30 of the fourth figure is taken as an example for illustration. The AC module 30 includes a protection circuit 308 in addition to the active clamp circuit 302, the power converter 304, and the AC selection switch circuit 306. The protection circuit 308 is electrically connected between the power converter 304 and the AC selection switch circuit 306. It is to be noted that the protection circuit 308 as shown in the seventh figure can be applied to all the implementations of the different AC modules 30, and therefore is not limited to this embodiment. The protection circuit 308 mainly comprises a series capacitor and a resistor (not shown), and a Zener diode and an auxiliary power switch (not shown). Wherein, the auxiliary power on relationship has a characteristic of low on-voltage. Therefore, the protection circuit 308 is configured to detect when the power conversion form number A0101 page 13/total 30 pages M408678 _: May 24, 2014, the output voltage of the pager 304 is replaced by a low voltage or zero voltage. In the zero-voltage crossing condition, the auxiliary power switch is turned on to maintain the power switches of the AC selection switch circuit 306 in an on state to ensure that the AC selection switch circuit 306 operates in a continuous conduction state. The power-on relationship of the AC selection switch circuit 306 is a silicon controlled rectifier (SCR). [0028] In summary, the present invention has the following advantages:

[0029] 1. The circuit of the present invention has a self-circuit protection function such as electrical isolation, self current current limiting (self current-limiting), etc. [0030] 2. Through the input low-voltage side switch with active clamping technology The zero-voltage flexible switching, through the high-voltage side rectifying diode to achieve zero-current flexible switching, and the AC-side switching switch for line frequency operation makes the creation circuit have high conversion efficiency characteristics; [0031] 3, the creation circuit has Active clamping technology, so the converter's working range is not limited to the requirement that the switching duty cycle of the conventional current source push-pull converter is greater than 50%. And on the high voltage side, the voltage doubler technology is adopted to further increase the input low voltage of the solar photovoltaic module to the AC mains voltage level, and the current is fed to the AC mains terminal. Therefore, the AC module of the present invention is very suitable. Low-power solar photovoltaic module in low-voltage wide input characteristics; [0032] 4. In terms of system reliability, the life of the power converter is mainly limited by the life of the electrolytic capacitor in the circuit and its operating environment temperature. No. A0101 Page 14 of 30 M408678 On May 24, 100, the electrolytic replacement capacitor circuit was not used in the circuit. The high voltage side voltage doubler capacitor is a small capacity film capacitor. Its purpose is to filter the switch. High frequency, emphasizing that its energy is passed on to assist the function of voltage boosting, rather than responsible for maintaining energy storage; [0033] 5. The high-voltage side circuit of the creation circuit adopts voltage doubler rectification, and does not need excessive high-frequency transformer turns ratio (turns) Rat i〇) can achieve voltage boost. In this way, not only the leakage inductance is reduced, but also the switching stress is reduced. Moreover, the switching elements of the circuit are flexibly switched, so the circuit has a long service life and high system reliability;

[0034] 6. The circuit of the present invention further provides the protection circuit, through the low on-voltage characteristic of the auxiliary power switch, to maintain the AC selection switch circuit in a low voltage or zero-voltage crossing operation. The power switches are in an on state to ensure that the AC selection switch circuit operates in a continuous conduction state. [0035] In summary, the solar photovoltaic module with flexible switching provided by the present invention is applied to a solar power generation system, so that the overall system conversion efficiency is improved, and the lack of the aforementioned conventional techniques is effectively improved, which has industrial value, and further Achieve the purpose of developing this creation. [0036] However, the above description is only for the detailed description and the drawings of the preferred embodiments of the present invention, but the features of the present invention are not limited thereto, and are not intended to limit the creation, and all the scope of the creation should be as follows. The scope of the patent application shall prevail, and the embodiments of the spirit of the patent application scope and similar changes shall be included in the scope of this creation. Anyone familiar with the art may easily in the field of this creation. Any changes or modifications considered may be covered by the patents in this case below. Form No. A0101 Page 15 of 30 M408678 Correction Replacement Page of May 24, 2014 [Simple Description of the Drawing] [0037] The first figure A is a block diagram of a conventional single-stage solar power parallel system; [0038] Figure B is a block diagram of a conventional two-stage solar power parallel system; [0039] The second figure is a block diagram of the present solar photovoltaic power generation system; [0040] The third figure is an active clamp circuit of the present communication AC module a circuit diagram of one of the first embodiments;

[0041] The fourth figure is a circuit diagram of a second embodiment of the active clamp circuit of the present invention; [0042] FIG. 5 is a third embodiment of the active clamp circuit of the present communication module [0043] FIG. 6 is a circuit diagram of a fourth embodiment of an active clamp circuit of the present invention; and [0044] FIG. 7 is a circuit diagram of another embodiment of the AC module of the present invention. [Main component symbol description]

[0010] 10 A Solar Photovoltaic Module [0047] 20 A Input Filter Capacitor [0048] 30 A DC/DC Converter [0049] 4 0 A DC/AC Converter [0050] 5 0 A AC mains [0051] Vpv DC output voltage form number A0101 Page 16 of 30 M408678 [0055] [0055] [0058] [0058] [0058] 100 years, May 24 Fix replacement page

[0060] [0064] [0067] [0070] [0070] I pv DC output current [this creation] 10 solar photovoltaic module 20 coupling capacitor unit 30 AC module 302 active clamp circuit 3022 first clamp switch 3024 second clamp switch 3026 first clamp capacitor 3028 second clamp capacitor 304 power converter 3042 first main switch 3044 second Main switch 306 AC selection switch circuit 3 0 8 Protection circuit 4 0 AC mains 50 line frequency switch 60 maximum power tracking controller 7 0 voltage / current detection circuit form number A0101 Page 17 / 30 pages M408678 _. 100 years May 24th according to the positive page [0071] 80 drive circuit [0072] Vpv DC output voltage [0073] I pv DC output current [0074] D1 diode [0075] D2 diode [0076] Crl filter capacitor [ 0077] Cr2 filter capacitor [0078] L i η input inductor [0079] Cc clamp capacitor form number A0101 Page 18 of 30

Claims (1)

Correction and replacement page M408678 on May 24, 100. VI. Patent application scope: 1. A solar photovoltaic power generation system provides a DC power supply through a solar photovoltaic module, and converts the DC power supply into an AC power supply, and then communicates with the AC power supply. The utility power is operated in parallel; the solar photovoltaic power generation system includes: a coupling capacitor unit electrically connecting the solar photovoltaic module to filter the DC power supply provided by the solar photovoltaic module; and an AC module electrically connected to the coupling capacitor unit to filter the capacitor The DC power supply is converted into a half sine wave current; the AC module includes: an active clamp circuit having a first clamp switch, a second clamp switch, a first home capacitor, and a second home a bit capacitor, receiving the chopped DC power supply to reduce a voltage surge of the filtered DC power supply; a power converter electrically connected to the active clamp circuit, having an isolation transformer, and the isolation transformer The primary side has a first main switch and a second main switch, and the secondary side of the isolation transformer has a rectifying circuit composed of two diodes and two filter capacitors to receive the DC power source and convert the DC power source. a DC voltage level and rectifying the DC power source; and an AC selection switch circuit electrically connecting the power converter to the AC mains, having a plurality of powers The full bridge structure formed by the switch is alternately switched in the synchronous manner of the AC mains; thereby, the half sine wave current is converted into a full sine wave current, and after filtering the high frequency switching component of the full sine wave current, The output current is purely sinusoidal and is in phase with the AC mains to achieve the maximum power point tracking control of the solar photovoltaic module and the unit power factor is fed into the AC mains. 2. For example, the solar photovoltaic power generation system of Patent Application No. 1 includes: 099222118 Form No. A0101 Page 19/Total 30 Page 1003184641-0 M408678 Correction of replacement page 1 line frequency switch, power supply Connecting the AC module and receiving the output voltage and current of the AC module to generate driving signals for driving the power switches of the AC selection switch circuit; a voltage/current detecting circuit electrically connecting the solar photovoltaic module And the coupling capacitor unit detects the output DC voltage and DC current of the solar photovoltaic module, and generates the first clamp switch and the second clamp switch and the power converter that drive the active clamp circuit a driving signal of the first main switch and the second main switch; a maximum power tracking controller electrically connecting the AC module and the voltage/current detecting circuit, and using the power outputted by the AC module to control the voltage/current detecting circuit and adjusting the sun a voltage or current operating point of the photovoltaic module to provide maximum power tracking control; and a driving circuit electrically connected to the voltage/current detecting circuit, the line frequency switching switch and the alternating current module, respectively receiving the voltage/ The current detecting circuit and the driving signals of the line frequency switching switch drive the active clamping circuit and the alternating current selection switch circuit. 3. The solar photovoltaic power generation system of claim 1, wherein the AC module further comprises a protection circuit electrically connected between the power converter and the AC selection switch circuit to detect when the power is When the output voltage of the converter is a low voltage or zero-voltage crossing condition, the power switches of the AC selection switch circuit are maintained in an on state. 4. The solar photovoltaic power generation system of claim 1, wherein the first clamp-on relationship of the active clamp circuit is complementary to the first main switch of the power converter, and the active clamp The second clamp-on relationship of the circuit is complementary to the second main switch of the power converter. 5. For example, the solar photovoltaic power generation system of claim 1 of the patent scope, wherein the power 099222118 form number A0101 page 20. total 30 pages 1003184641-0 100 years on May 24th nuclear correction page conversion benefits s Xuan first The main open relationship is out of phase with the second main switch switching timing of the power converter. Such as Shen. In the solar photovoltaic power generation system of the first aspect of the patent, wherein the first clamp-on relationship of the active #bit circuit is switched with the first main switch of the power converter, and, ! When the second clamp-on relationship is switched with the second main switch of the power converter, a dead time is provided for soft switching. 7. The solar photovoltaic power generation system of claim 1, wherein the power converter is a current-fed push-pull converter. 8. The solar photovoltaic power generation system of claim 1, wherein the power-on relationship of the alternating current selection switch circuit is a metal-oxide-semi-conductor field effect transistor (MOSFET). 9. The solar photovoltaic power generation system of claim i, wherein the power-on relationship of the AC selection switch circuit is a controlled rectifier (SCR). 10 - The solar photovoltaic power generation system of claim 1, wherein the isolation transformer of the power converter provides double voltage rectification for the secondary side center tap to improve the output voltage of the solar photovoltaic module. It is placed at the AC mains level and can be fed into the AC mains in the form of a current source. 11 · An AC module of a solar photovoltaic power generation system, which receives a DC power source and converts the DC power source into an AC power source, and then runs in parallel with an AC power supply; the AC module includes: an active clamp circuit, Having a first clamp switch 'a second clamp switch, a first clamp capacitor and a second clamp capacitor, receiving the DC form number A0101 page 21 / 30 pages 1003184641-0 M408678 __, 100 years The replacement page source is modified on May 24 to reduce the voltage surge of the DC power source; a power converter is electrically connected to the active clamp circuit, and has an isolation transformer, and the primary side of the isolation transformer has a first a main switch and a second main switch, the secondary side of the isolation transformer has a rectifying circuit composed of two diodes and two filter capacitors, to receive the DC power source, and convert the DC voltage level of the DC power source and Rectifying the DC power supply: and An AC selection switch circuit is electrically connected to the power converter and the AC mains, and has a full bridge structure formed by a plurality of power switches, and is alternately switched in an AC mains synchronous manner; thereby converting half of the sine wave current into one full The sinusoidal current, after filtering the high-frequency switching component of the full sine wave current, can make the output current pure sinusoid and be in phase with the AC mains to achieve the maximum power point tracking control and unit work of the solar photovoltaic module Because of the feeding of the exchange city power. 12. The AC module of the solar photovoltaic power generation system of claim 11, wherein the AC module further comprises a protection circuit electrically connected between the power converter and the AC selection switch circuit to detect When the output voltage of the power converter is a low voltage or zero-voltage crossing condition, the power switches of the AC selection switch circuit are maintained in an on state. 13. The AC module of the solar photovoltaic power generation system of claim 11, wherein the first clamp-on relationship of the active clamp circuit and the first main switch of the power converter are compensated switching, and The second clamp-on relationship of the active clamp circuit is complementary to the second main switch of the power converter. 14 For example, the AC module of the solar photovoltaic system of the 11th patent application, 099222118 Form No. A0101 Page 22 / Total 30 Page 1003184641-0 Correction of the replacement page of the year of the power converter The main open relationship is 180 degrees out of phase with the second main switch switching timing of the power converter.丨5. The AC module of the solar photovoltaic power generation system of claim 11, wherein the first clamp-on relationship of the active clamp circuit is switched with the first-main switch of the power converter, and When the second clamp-on relationship is switched with the second main switch of the power converter, a blind time ((^34 time) is provided for flexible switching (s〇f1; switching). The AC module of the solar photovoltaic power generation system, Φ, wherein the power converter is a current-fed push-pull converter (.) The AC module of the solar photovoltaic power generation system, wherein the power-on relationship of the AC selection switch circuit is a metal-oxide-semiconductor* "eld effect transistor (MOSFET). The AC module of the solar photovoltaic power generation system of the first aspect of the patent, wherein the power-on relationship of the AC selection switch circuit is a si 1 icon contro11ed rectifier (SCR). 19. The AC module of the solar photovoltaic power generation system of claim 11, wherein the isolation transformer of the power converter is a primary side center tap and a secondary side providing voltage doubler rectification to enhance the solar photovoltaic power generation The system output voltage is leveled to the AC mains level, and the current source can be fed into the AC mains. 099222118 Form No. A0101 Page 23 / Total 30 Page 1003184641-0