TWI502875B - Dc/ac converter for solar photovoltaic module - Google Patents

Description

DC to AC conversion device applied to solar photovoltaic module

The invention relates to a DC-to-AC conversion device applied to a solar photovoltaic module, and particularly relates to a DC-to-AC conversion device for converting a DC power source of a solar photovoltaic module into an AC power source and feeding the power grid.

Based on the shortage of petrochemical energy and the awareness of environmental protection, renewable energy is a technological field that has been actively developed in recent years. Among them, solar cells are important industries that are actively developed in many countries due to their high theoretical efficiency and mature technology. . In addition, in terms of solar power generation technology, the small-capacity and modular solar power generation device has the characteristics of improving system power generation efficiency, speeding up user cost recovery, and easy installation by users, and has become the mainstream of today's renewable energy.

The solar photovoltaic module mainly performs photoelectric conversion through the solar panel to generate a DC power source, and then converts the DC power source into an AC power source by the converter for the load to use or feed into the power grid, and synchronously runs in parallel with the power grid. In general, the converter circuit architecture used in solar photovoltaic modules uses a two-stage switching mode. For example, in a low-frequency isolated DC-to-AC converter, the output voltage of the rear-stage AC conversion circuit is the AC power required to obtain the load after the buck-boost of the low-frequency transformer, but the low-frequency transformer is bulky and heavier, and the output power is Limited by the power level of the low frequency transformer.

In another example, a high-frequency isolated DC-to-AC converter uses a DC converter to control the voltage at the output of the DC link, and then transfers the energy to the secondary side through the high-frequency transformer through high-frequency switching. The secondary side output is connected in parallel with the capacitor for circuit filtering and energy storage. Although the volume and output power of the high-frequency converter are not affected by the transformer, the switching loss is also increased with the increase of the switching frequency due to the operation of the high-frequency converter, so that the conversion efficiency of the circuit is not easily improved. In addition, the input terminal of the rear-stage AC converter circuit uses the above-mentioned capacitor connected in parallel with the secondary side output terminal of the high-frequency transformer as an energy buffer between the circuits, so the capacitance of the capacitor increases with the power of the converter. With the increase, the circuit volume and cost also increase. Furthermore, high-capacitance capacitors typically use electrolytic capacitors, which reduces system reliability.

In view of this, the present disclosure provides a DC-to-AC conversion device applied to a solar photovoltaic module, which converts a DC power outputted by a solar photovoltaic module into an AC power source and feeds the power grid, operates in a high frequency mode, and can be reduced. Switch losses and avoid transformer saturation to improve conversion efficiency and increase system reliability.

An embodiment of the present invention provides a DC-to-AC conversion device for a solar photovoltaic module, comprising: an isolated single-ended primary inductance conversion circuit, comprising an isolation transformer having three sets of coils for using a solar photovoltaic module The output DC voltage is converted into an AC voltage; and an angle and phase control circuit receives the AC voltage and controls the output power angle and phase of the AC voltage, and feeds the AC voltage to a power grid.

a, b‧‧‧ input

C _a ‧‧‧DC isolation capacitor

C _in ‧‧‧ capacitor

D _a , D _b ‧‧‧ Passive diode components

i _ac ‧‧‧Output AC current

i _S1 , i _Da , i _Db ‧ ‧ current

L ₁ ‧‧‧ storage inductor

S ₁ , S _a , S _b , S _a1 , S _b1 ‧‧‧ active switching elements

T‧‧‧Transformer

T _p ‧‧‧ primary side coil

T _sa , T _sb ‧‧‧ secondary coil

V _GS1 , V _GSa , V _GSb ‧‧‧ control signals

FIG. 1 is a block diagram showing a DC-to-AC conversion device applied to a solar photovoltaic module according to an embodiment of the invention.

2 is a circuit diagram of a DC-to-AC converter applied to a solar photovoltaic module according to an embodiment of the invention.

Fig. 3 is a signal timing diagram of the DC-to-AC converter applied to the solar photovoltaic module of Fig. 2.

4A to 4B are schematic diagrams showing the operation of the DC-to-AC converter applied to the solar photovoltaic module in the positive half cycle of the grid in Fig. 2.

5A to 5B are schematic diagrams showing the operation of the DC-to-AC converter applied to the solar photovoltaic module in the negative half cycle of the grid in Fig. 2.

Figure 6 is a schematic diagram of a DC-to-AC converter applied to a solar photovoltaic module in accordance with an embodiment of the present invention.

Figure 7 is a schematic diagram of a DC-to-AC converter applied to a solar photovoltaic module in accordance with an embodiment of the present invention.

Figure 8 is a schematic diagram of a DC-to-AC converter applied to a solar photovoltaic module in accordance with an embodiment of the present invention.

Figure 9 is a schematic diagram of a DC-to-AC converter applied to a solar photovoltaic module in accordance with an embodiment of the present invention.

The following description is an embodiment of the present invention. The intent is to exemplify the general principles of the invention and should not be construed as limiting the scope of the invention, which is defined by the scope of the claims.

It is worth noting that the content disclosed below can provide multiple uses. Embodiments or examples that embody different features of the invention. The specific elements and arrangements of the elements described below are merely illustrative of the spirit of the invention and are not intended to limit the scope of the invention. In addition, the following description may reuse the same component symbols or characters in various examples. However, the re-use is for the purpose of providing a simplified and clear description, and is not intended to limit the relationship between the various embodiments and/or configurations discussed below. In addition, the description of one of the features described in the following description, which is connected to, coupled to, and/or formed on another feature, etc., may actually include a plurality of different embodiments, including direct contact of the features, or other Additional features are formed between the features, etc. such that the features are not in direct contact.

1 is a block diagram of a DC-to-AC converter 20 applied to a solar photovoltaic module 10 for converting a DC voltage outputted by a solar photovoltaic module 10 into an AC voltage and feeding it into a power grid according to an embodiment of the invention. CG. The DC-to-AC converter 20 includes an isolated Single Ended Primary Inductor Converter (SEPIC) circuit 200 and an angle and phase control circuit 300. The isolated single-ended primary inductance conversion circuit 200 converts the above-mentioned DC voltage into an AC voltage, including an isolation transformer T. The angle and phase control circuit 300 receives the AC voltage of the isolated single-ended primary inductance conversion circuit 200 and controls the output power angle and phase of the AC voltage of the isolated single-ended primary inductance conversion circuit 200, and then feeds the AC current to the grid CG.

2 is a circuit diagram of a DC-to-AC converter applied to a solar photovoltaic module according to an embodiment of the invention. As shown in FIG. 2, the isolated single-ended primary inductance conversion circuit 200 includes input terminals a and b, a capacitor C _in , a storage inductor L ₁ , a DC isolation capacitor C _a , an active switching element S _{1 ,} and an isolation transformer T. The input terminals a and b receive the DC voltage outputted by the solar photovoltaic module, wherein the input terminal a is coupled to the positive terminal of the DC voltage, and the input terminal b is coupled to the negative terminal of the DC voltage. The capacitor C _{in is} coupled between the input terminals a and b, the first end of the storage inductor L ₁ is coupled to the input end a, and the second end of the storage inductor L ₁ is coupled to the first of the DC isolation capacitor C _a and an active terminal end of the first switching element S _1, a second end of the active switching element S ₁ is coupled to the input terminal B, the switching control terminal of the active element S ₁ (gate terminal) is coupled to a control circuit (not Show). The isolation transformer T is an isolation transformer of a three-coil group, and includes a primary side coil T _p and a secondary side coil T _sa and T _sb , wherein the first end of the primary side coil T _p is coupled to the second of the DC isolation capacitor C _a The second end of the primary side coil T _p is coupled to the input end b, and the first end of the primary side coil T _{p and} the first end of the secondary side coil T _{sa and} the first end of the secondary side coil T _sb Have the same polarity (shown by black dots in the figure). The second end of the secondary side coil T _{sa and} the first end of the secondary side coil T _sb are coupled to the second end of the grid CG. In the present disclosure, the grid CG refers to the alternating current bus of the power supply.

The angle and phase control circuit 300 includes active switching elements S _a and S _b and passive diode elements D _a and D _b . The active switching element S _a is a positive half-cycle active switching element, the first end of which is coupled to the first end of the secondary side coil T _{sa and} the second end of which is coupled to the anode end of the passive diode element D _a . The cathode end of the passive diode element D _a is coupled to the first end of the grid CG. The active switching element S _b is a negative half cycle active switching element, the first end of which is coupled to the first end of the power grid CG and the second end of which is coupled to the anode end of the passive diode element D _b . The cathode end of the passive diode element is coupled to the second end of the secondary side coil T _sb . Active switching elements S _a and S _b of the control terminal coupled to said control circuit (not shown), the control circuit may be an analog or digit integrated circuit for controlling the active switching element S _1, S _a, and The conduction and cutoff of S _b .

When the grid CG of the sine wave in the positive half cycle, the positive half cycle of active switching element S _a passive diode D _a is turned on, the output current of the transformer T i _Da through the conducting active switching element S _a passive diode D _{a is} transmitted to the grid CG, and at this time, the negative half-cycle active switching element S _b and the passive diode D _b are non-conducting; when the sine wave of the grid CG is in the negative half cycle, the negative half-cycle active switching element S _b and passive diode D _b is turned on, the output current of the transformer T i _Db transmitted through the conducting active switching element S _b and passive diode D _b to the grid the CG, and this time the positive half cycle of active switching element S _a passive two The polar body D _a is non-conductive.

Figure 3 is a signal timing diagram of the DC-to-AC converter used in the solar photovoltaic module of Figure 2, which will be applied to the solar photovoltaic module in accordance with Figs. 4A to 4B and 5A to 5B. The operation of the DC-to-AC converter, wherein Figures 4A to 4B are diagrams of the operation of the DC-to-AC converter applied to the solar module in Figure 2 in the positive half cycle of the grid, and Figures 5A to 5B are the second The schematic diagram of the operation of the DC-to-AC converter used in the solar photovoltaic module in the negative half cycle of the grid.

When the sine wave of the power grid CG is in the positive half cycle, if the control circuit turns on the active switching element S ₁ by the control signal V _GS1 (that is, controls the path between the first end and the second end of the active switching element S ₁ ), as shown in Figure 4A, the energy storage inductor L ₁ begins to store energy, the DC blocking capacitor C _a T _p of the primary side coil to release energy, and therefore the primary-side current i _S1 starts to increase linearly. When the sine wave of the grid CG is in the positive half cycle, if the control circuit turns off the active switching element S ₁ after the active switching element S _{1 is} turned on for a predetermined time, as shown in FIG. 4B, the storage inductor L ₁ is connected to the DC isolation capacitor. C _a releases energy, and the primary side coil T _p transmits energy to the secondary side coil T _sa . At this time, when the sine wave of the power grid CG is in the positive half cycle, the control circuit conducts the positive half cycle active by the control signal V _{GSa .} S _a switching element (in FIG. 2 as the control signal V _GSa shown), thus the secondary winding T _sa conduction control circuit through the positive half cycle of the phase angle of the switching element S _a active and passive elements diode D _a will Energy is fed into the grid CG as shown in Figure 4B. Each time when the control circuit detects that the inductor L ₁ discharging current is zero, the control circuit will be turned active switching element S _1, and is turned off after a predetermined time of the active switching elements S _1, when the active switching elements S _{At the} end of ₁ time, the energy storage inductor L1 releases energy until the release current is zero, and then repeats the above steps when the control circuit detects that the discharge current of the energy storage inductor L ₁ is zero. Therefore, as shown in the graph of the control signal V _GS1 in FIG. 3, the active switching element S ₁ is turned on repeatedly for a predetermined time and then turned off, and the operation of the active switching element S _{1 when} turned on and off is as described above. repeat.

When the sine wave of the power grid CG is in the negative half cycle, if the control circuit turns on the active switching element S ₁ by the control signal V _GS1 , as shown in FIG. 5A , the energy storage inductor L ₁ starts to store electrical energy, and the DC isolation capacitor C _a T _p of the primary side coil to release energy, and therefore the primary-side current i _S1 starts to increase linearly. When the sine wave of the power grid CG is in the positive half cycle, if the control circuit turns off the active switching element S ₁ after the active switching element S _{1 is} turned on for a predetermined time, as shown in FIG. 5B, the energy storage inductor L ₁ is connected to the DC isolation capacitor. C _a releases energy, and the primary side coil T _p transfers energy to the secondary side coil T _sb . At this time, when the sine wave of the power grid CG is in the negative half cycle, the control circuit conducts the negative half cycle active by the control signal V _{GSb .} The switching element S _b (shown as control signal V _GSb in FIG. 2 ), so that the secondary side coil T _sb transmits the negative half-cycle active switching element S _b and the passive diode element D _b that are turned on in the angle and phase control circuit Energy is fed into the grid CG as shown in Figure 5B. Each time when the control circuit detects that the inductor L ₁ discharging current is zero, the control circuit will be turned active switching element S _1, and is turned off after a predetermined time of the active switching elements S _1, when the active switching elements S _{At the} end of ₁ time, the energy storage inductor L1 releases energy until the release current is zero, and then repeats the above steps when the control circuit detects that the discharge current of the energy storage inductor L ₁ is zero. Therefore, as shown in the graph of the control signal V _GS1 in FIG. 3, the active switching element S ₁ is turned on repeatedly for a predetermined time and then turned off, and the operation of the active switching element S _{1 when} turned on and off is as described above. repeat. In the disclosure, the active switching element may be a transistor, such as a Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET) or an Insulated Gate Bipolar Transistor (IGBT). It can also be a Silicon Controlled Rectifier (SCR) or a Gate Turn Off (GTF).

Through the DC-to-AC conversion device described above, the DC power output from the solar photovoltaic module can be converted into AC power and fed to the grid CG, as shown by the output AC current i _ac in FIG. The isolated single-ended primary inductance conversion circuit in the DC-to-AC converter of the above embodiment has a current source characteristic, which can reduce the current chain wave on the input side, and adopts boundary conduction technology, each time the inductor current (ie, the energy storage inductor L) _When the discharge current of ₁ is zero, the active switching element S ₁ is controlled to be turned on. Therefore, the active switching element S ₁ has a characteristic of zero voltage switching (ZVS), which can reduce the switching loss of the switching element. In addition, with the active control circuit for controlling the conduction time of the switching element S ₁ may control the output power.

Since the active switching element S _{1 is} in the high frequency switching mode and the transformer T is the isolation transformer, the isolated single-ended primary inductance conversion circuit can be reduced in size in circuit design. In addition, the DC isolation capacitor in the isolated single-ended primary inductance conversion circuit can remove the DC component of the transformer T, so the film capacitor can be used instead of the electrolytic capacitor to improve the reliability of the system. The secondary side coil of the isolated single-ended primary inductance conversion circuit is electrically coupled to the angle and phase control circuit, and the angular and phase control circuit transmits the active switching elements S _a and S _b and the passive diode through synchronous switching with the grid CG frequency. element D _a and D _b controls the AC output of the power angle and the phase, to achieve the grid results in synchronization with the grid, and since the active switches S _a and the switching frequency of the grid CG frequency S _b (e.g., 60Hz) element synchronized, The switching loss of the switching element is very low. In addition, since the number of circuit components required for the DC-to-AC converter of the present embodiment is smaller than that of the prior art, the system cost can be reduced.

The difference between the following embodiments and the embodiment of FIG. 2 mainly lies in the angle and phase control circuit. Therefore, the following mainly describes the difference between the angle and phase control circuits, and the rest of the similar parts are as described above and will not be described again.

Figure 6 is a schematic diagram of a DC-to-AC converter applied to a solar photovoltaic module in accordance with another embodiment of the present invention. The angle and phase control circuit of Figure 6 includes active switching elements S _a and S _b and passive diode elements D _a and D _b . The active switching element S _a is a positive half-cycle active switching element, the first end of which is coupled to the second end of the power grid CG, and the second end of which is coupled to the second end of the secondary side coil T _sa . The anode end of the passive diode element D _a is coupled to the first end of the secondary side coil T _sa , and the cathode end thereof is coupled to the first end of the grid CG. The active switching element S _b is a negative half-cycle active switching element, the first end of which is coupled to the first end of the secondary side coil T _{sb and} the second end of which is coupled to the second end of the power grid CG. The cathode end of the passive diode element D _b is coupled to the second end of the secondary side coil T _sb , and the anode end thereof is coupled to the first end of the grid CG. Active switching elements S _a and S _b is turned on and off controlled by the control circuit, when the grid CG of the sine wave in the positive half cycle, the positive half cycle of active switching element S _a passive diode D _a is turned on, the transformer T output current i _Da through the active switching element of S _a and passive diode transmits D _a to the grid CG, and at this time a negative half cycle active switching element S _b and passive diode D _b nonconducting; when the grid CG is When the sine wave is in the negative half cycle, the negative half cycle active switching element S _b and the passive diode D _b are turned on, and the output current i _{Db of the} transformer T is transmitted to the active switching element S _b and the passive diode D _{b that are} turned on to grid CG, and at this time active positive half cycle and the switching element S _a passive diode D _a nonconducting.

Figure 7 is a schematic diagram of a DC-to-AC converter applied to a solar photovoltaic module in accordance with another embodiment of the present invention. The angle and phase control circuit of Figure 7 includes active switching elements S _a , S _a1 , S _b and S _b1 . Active switching elements Sa ₁ and S _a is a positive half cycle of the switching active element, the active terminal of the switching element S _a second terminal coupled to a first power grid CG of active switching element S _a second terminal coupled to the secondary side a first terminal coupled to a first end of the grid CG, a second terminal coupled to the active switching element S _a1 is coupled to the secondary winding T _sa first and second ends of the coil T _sa, S _a1 is the active switching element. The active switching elements S _b and S _b1 are negative half-cycle active switching elements, the first end of the active switching element S _b is coupled to the first end of the secondary side coil T _sb , and the second end of the active switching element S _b is coupled To the second end of the power grid CG, the first end of the active switching element S _b1 is coupled to the second end of the secondary side coil T _sb , and the second end of the active switching element S _b1 is coupled to the first end of the power grid CG. The active switching elements S _a , S _a1 , S _b and S _b1 are controlled to be turned on and off by the above control circuit. When the sine wave of the power grid CG is in the positive half cycle, the positive half cycle active switching elements S _a and S _a1 are turned on and output. current i _{Da a1} transmitted through the conducting active switching element S _a and S to the grid CG, and at this time a negative half cycle active switching elements S _B and S _B1 is not turned on; when the grid CG is a sine wave in the negative half cycle, the negative half cycle active switching element S _b and S _b1 transmitted through the conducting active switching element S _b and S _b1 to the grid CG is turned on, the output current i _Db, and this time the positive half cycle of active switching element S _a and S _a1 nonconducting .

Figure 8 is a schematic diagram of a DC-to-AC converter applied to a solar photovoltaic module in accordance with another embodiment of the present invention. The angle and phase control circuit of Figure 8 includes active switching elements S _a and S _b and passive diode elements D _a and D _b . The active switching element S _a is a positive half-cycle active switching element, the first end of which is coupled to the first end of the secondary side coil T _sa , and the second end of which is coupled to the first end of the power grid CG . The anode end of the passive diode element D _a is coupled to the second end of the grid CG, and the cathode end thereof is coupled to the second end of the secondary side coil T _sa . The active switching element S _b is a negative half-cycle active switching element, the first end of which is coupled to the first end of the power grid CG and the second end of which is coupled to the second end of the secondary side coil T _sb . The anode end of the passive diode element D _b is coupled to the first end of the secondary side coil T _sb , and the cathode end thereof is coupled to the second end of the grid CG. Active switching elements S _a and S _b Control turned on and off by the control circuit, when the grid CG of the sine wave in the positive half cycle, the positive half cycle of active switching element S _a passive diode D _a is turned on, the output current i _Da transmitted through conducting active switching element S _a passive diode D _a to the grid CG, and at this time a negative half cycle active switching element S _b and passive diode D _b nonconducting; when the grid CG is sinusoidal in During the negative half cycle, the negative half cycle active switching element S _b and the passive diode D _b are turned on, and the output current i _{Db is} transmitted to the power grid CG through the turned-on active switching element S _b and the passive diode D _b . active positive half cycle and the switching element S _a positive half cycle of the passive diode D _a nonconducting.

Figure 9 is a schematic diagram of a DC-to-AC converter applied to a solar photovoltaic module in accordance with another embodiment of the present invention. The angle and phase control circuit of Fig. 9 includes active switching elements S _a , S _a1 , S _b and S _b1 . Active switching elements Sa ₁ and S _a is a positive half cycle of the switching active element, a first terminal coupled to the active switching element S _a is coupled to a first end of the secondary winding T _sa, active switching element S _a second terminal coupled To the second end of the active switching element S _a1 , the active switching elements S _a and Sa ₁ are connected to each other, and the first end of the active switching element S _a1 is coupled to the first end of the power grid CG. The active switching elements S _b and S _b1 are negative half-cycle active switching elements, the first end of the active switching element S _b is coupled to the first end of the power grid CG, and the second end of the active switching element S _b is coupled to the active switching element The second end of the S _b1 , the first end of the active switching element S _b1 is coupled to the second end of the secondary side coil T _sb . The active switching elements S _a , S _a1 , S _b and S _b1 are controlled to be turned on and off by the above control circuit. When the sine wave of the power grid CG is in the positive half cycle, the positive half cycle active switching elements S _a and S _a1 are turned on and output. current i _{Da a1} transmitted through the conducting active switching element S _a and S to the grid CG, and at this time a negative half cycle active switching elements S _B and S _B1 is not turned on; when the grid CG is a sine wave in the negative half cycle, the negative half cycle active switching element S _b and S _b1 transmitted through the conducting active switching element S _b and S _b1 to the grid CG is turned on, the output current i _Db, and this time the positive half cycle of active switching element S _a and S _a1 nonconducting .

The above is an overview feature of the embodiment. Those having ordinary skill in the art should be able to use the present invention as a basis for design or adaptation to achieve the same objectives and/or achieve the same advantages of the embodiments described herein. It should be understood by those of ordinary skill in the art that the same configuration should not depart from the spirit and scope of the present invention, and various changes, substitutions and substitutions can be made without departing from the spirit and scope of the present invention. The illustrative methods are merely illustrative of the steps, but are not necessarily performed in the order presented. Additional The steps of adding, replacing, changing the order and/or eliminating the steps are adjusted as appropriate and are consistent with the spirit and scope of the disclosed embodiments.

a, b‧‧‧ input

C _a ‧‧‧DC isolation capacitor

C _in ‧‧‧ capacitor

D _a , D _b ‧‧‧ diode

i _S1 , i _Da , i _Db , i _ac ‧ ‧ current

L ₁ ‧‧‧ storage inductor

CG‧‧‧ grid

S ₁ , S _a , S _b ‧‧‧ active switching elements

T‧‧‧Transformer

T _p ‧‧‧ primary side coil

T _sa , T _sb ‧‧‧ secondary coil

Claims (12)

A DC-to-AC conversion device for a solar photovoltaic module, comprising: an isolated single-ended primary inductance conversion circuit, comprising an isolation transformer having three sets of coils for converting a DC voltage outputted by a solar photovoltaic module An AC voltage; and an angle and phase control circuit, receiving the AC voltage and controlling an output power angle and phase of the AC voltage, and feeding the AC voltage to a power grid; wherein the three sets of coils include a primary side coil, a secondary side coil and a second secondary side coil, the isolated single-ended primary inductance conversion circuit further includes an active switching element coupled to the primary side coil, the angle and phase control circuit including coupling to the first a secondary side coil and a first active switching element of the power grid and a second active switching element coupled to the second secondary side coil and the power grid; wherein the isolated single-ended primary inductance conversion circuit further comprises: a first input end coupled to the positive end of the DC voltage; a second input end coupled to the negative end of the DC voltage; a storage inductor, The first end of the energy storage inductor is coupled to the first input end, the second end of the energy storage inductor is coupled to the first end of the active switching element, and the DC isolation capacitor, wherein the DC isolation capacitor is One end is coupled to the first end of the active switching element, and the second end of the DC isolation capacitor is coupled to the first end of the primary side coil; wherein the second end of the primary side coil and the first end of the active switching element The two ends are coupled to the second input end, and the first end of the primary side coil The first end of the first secondary side coil and the first end of the second secondary side coil have the same polarity. The DC-to-AC conversion device for a solar photovoltaic module according to the first aspect of the invention, further comprising: a control circuit coupled to the control end of the active switching element and the control end of the first active switching element And a control end of the second active switching element for controlling conduction and deactivation of the active switching element, the first active switching element, and the second active switching element. The DC-to-AC conversion device for a solar photovoltaic module according to the first aspect of the invention, wherein the isolated single-ended primary inductance conversion circuit further includes: a capacitor coupled to the first input terminal and the first Between the two inputs. The DC-to-AC conversion device applied to a solar photovoltaic module according to claim 3, wherein the first active switching element is turned on when the sine wave of the power grid is in a positive half cycle, and the second active switch The component is turned off, and the active switching component is turned on repeatedly for a predetermined time, and the energy storage inductor stores energy when the active switching component is turned on. When the active switching component is turned off, the energy storage inductor is released to zero current. And when the sine wave of the power grid is in a negative half cycle, the second active switching element is turned on, the first active switching element is turned off, and the active switching element is continuously turned on repeatedly for a predetermined time and then cut off when the active When the switching element is turned on, the energy storage inductor stores electrical energy, and when the active switching element is turned off, the energy storage inductor releases energy to zero. The DC-to-AC converter of the solar photovoltaic module of claim 4, wherein the first end of the first active switching element is coupled to the first end of the first secondary coil, The first end of the second active switching element is coupled to the first end of the power grid, and the second end of the first secondary side coil and the first end of the second secondary side coil are coupled to the second end of the power grid And the angle and phase control circuit further includes: a first passive diode component, wherein an anode end of the first passive diode component is coupled to a second end of the first active switching component, the first a cathode end of the passive diode component coupled to the first end of the power grid; and a second passive diode component, wherein an anode end of the second passive diode component is coupled to the second active switching component The second end of the second passive diode element is coupled to the second end of the second secondary side coil. The DC-to-AC converter of the solar photovoltaic module of claim 4, wherein the first end of the first active switching element is coupled to the second end of the power grid, the first active switching component The second end is coupled to the second end of the first secondary side coil, the first end of the second active switching element is coupled to the first end of the second secondary side coil, the second active switching element The second end is coupled to the second end of the power grid, and the angle and phase control circuit further includes: a first passive diode component, wherein an anode end of the first passive diode component is coupled to the first a first end of the secondary side coil, a cathode end of the first passive diode element coupled to the first end of the power grid; and a second passive diode element, wherein the second passive diode element The cathode end is coupled to the second end of the second secondary side coil, and the anode end of the second passive diode element is coupled to the first end of the power grid. The DC-to-AC converter of the solar photovoltaic module of claim 4, wherein the first end of the first active switching element is coupled to the second end of the power grid, the first active switching component The second end is coupled to the second end of the first secondary side coil, the first end of the second active switching element is coupled to the first end of the second secondary side coil, the second active switching element The second end is coupled to the second end of the power grid, and the angle and phase control circuit further includes: a third active switching element, wherein the first end of the third active switching element is coupled to the first end of the power grid The second end of the third active switching element is coupled to the first end of the first secondary side coil; and a fourth active switching element, wherein the first end of the fourth active switching element is coupled to the first end a second end of the second secondary side coil, the second end of the fourth active switching element is coupled to the first end of the power grid. The DC-to-AC converter of the solar photovoltaic module of claim 4, wherein the first end of the first active switching element is coupled to the first end of the first secondary coil, The second end of the first active switching element is coupled to the first end of the power grid, the first end of the second active switching element is coupled to the first end of the power grid, and the second end of the second active switching element The second end of the second secondary side coil is coupled to the phase control circuit, and the angle control circuit further includes: a first passive diode element, wherein an anode end of the first passive diode element is coupled to the power grid a second end of the first passive diode element coupled to the second end of the first secondary side coil; and a second passive diode element, wherein the second passive diode element The anode end is coupled to the first end of the second secondary side coil, and the cathode end of the second passive diode element is coupled to the second end of the power grid. The DC-to-AC converter of the solar photovoltaic module of claim 4, wherein the first end of the first active switching element is coupled to the first end of the first secondary coil, The first end of the second active switching element is coupled to the first end of the power grid, and the second end of the first secondary side coil and the first end of the second secondary side coil are coupled to the second end of the power grid And the angle and phase control circuit further includes: a third active switching element, wherein the first end of the third active switching element is coupled to the first end of the power grid, and the second end of the third active switching element a second end coupled to the first active switching element; and a fourth active switching element, wherein the first end of the fourth active switching element is coupled to the second end of the second secondary side coil, the first The second end of the four active switching elements is coupled to the second end of the second active switching element. The DC-to-AC conversion device for a solar photovoltaic module according to claim 1, wherein the active switching element, the first active switching element, and the second active switching element are MOS field effect transistors , insulated gate bipolar transistor, 矽 controlled rectifier or gate closing element. The DC-to-AC conversion device applied to a solar photovoltaic module according to claim 7, wherein the third active switching element and the fourth active switching element are MOSFETs, insulated gate bipolar A transistor, a controlled rectifier or a gate closing element. The DC-to-AC conversion device for a solar photovoltaic module according to claim 9, wherein the third active switching element and the fourth active switching element are MOS field effect transistors, and insulating gate bipolar A transistor, a controlled rectifier or a gate closing element.