TW201820763A - Three-port DC-AC power converter and control method thereof - Google Patents

Abstract

A three-port DC-AC power converter includes a first T-type power electronic arm, a second T-type power electronic arm, a capacitor arm, a decoupling circuit, a filter inductor set, a first filter capacitor, a second filter capacitor and a controller. The three-port DC-AC power converter has a DC input port, a first AC output port and a second AC output port. The decoupling circuit is provided to decouple different-frequency AC components supplied from the first T-type power electronic arm and the second T-type power electronic arm, thereby supplying two AC sinusoidal voltages only with a single power converter that can simplify the entire circuit.

Description

Three-turn DC-AC power conversion device and control method thereof

The present invention relates to a three-port three-port DC-AC power conversion device and a control method thereof; and more particularly to a dual-frequency three-turn DC-AC power conversion device and a control method thereof.

Conventional DC-AC power conversion device, for example, the power conversion circuit of the Republic of China Patent No. I327812 and its control circuit and invention patent, which discloses the structure of the power conversion circuit. The power conversion circuit includes a step-down converter, a bypass passive switching element, and a continuous-flow AC converter. The power conversion circuit only has a single-direction power flow, so a battery charger is required for charging, and the low-voltage DC voltage is first converted into a high-voltage DC voltage during discharge, and then the high-voltage DC voltage is converted into AC power. The discharge must be converted by two stages, which inevitably causes a large energy loss.

Another conventional DC-AC power conversion device, for example, the online uninterruptible power supply device of the Republic of China Patent No. I363464, is an invention patent, which discloses the architecture of an online uninterruptible power supply device. The online uninterruptible power supply device comprises a filtering device, a rectifying device, a battery device, a switch, a DC/DC converter, a DC/AC converter, a relay and a filter. Since the online uninterruptible power supply device must pass the DC/DC conversion device and the DC/AC conversion device, the DC power of the low voltage battery can be converted into an AC power supply, and the straight The current/DC converter has a high-frequency isolation transformer. This circuit must use a large number of power switching components and power diodes, thus causing an increase in equipment cost, and the battery discharge must be converted by two stages and a transformer, which inevitably results in a larger Energy loss.

Another conventional DC-AC electric energy conversion device, for example, the single-phase three-wire three-turn electric energy conversion system of the Republic of China Patent No. I462457, discloses a single-phase three-wire three-turn electric energy conversion system, which comprises a The single-phase three-wire three-turn power converter has a high-voltage DC input/output port, a low-voltage DC input/output port, and an AC input/output port, and the circuit includes a bridge type power converter, a filter inductor group, and a decoupling loop. a filter capacitor bank and a controller. The bridge type power converter comprises three power electronic switch arms and a capacitor arm; the high voltage DC input/output port can be connected to a DC voltage source, which is a power source converted by a power converter, a solar array or Other high voltage DC power supply; the decoupling circuit is composed of two capacitors; the low voltage DC input/output port is connected to another DC voltage source, which is a solar cell array, a fuel cell, a battery pack or other low voltage DC power source. The AC input/output port is connected to the single-phase three-wire power distribution system via a switch group, and a load group is connected between the AC input/output port and the switch group. The single-phase three-wire three-turn power converter can simultaneously convert energy between high-voltage DC input/output ports, low-voltage DC input/output ports, and AC input/output ports.

In general, when performing conventional DC-AC power conversion, a motor generator set or a solid state power electronic converter can be selected for power conversion. When the motor-generator set is selected, it has a problem of bulkiness and inefficiency. In contrast, when the solid-state power electronic converter is selected, it has the advantages of small volume, high energy density, and high efficiency. However, regardless of whether the motor-generator set or solid state power electronic converter is selected, only one set of AC sinusoidal voltages can be output. Therefore, if you need to provide two sets of AC sine wave voltages with different frequencies, you need to use two independent groups. The motor-generator set or the DC-AC power converter can achieve the simultaneous output of two sets of AC sinusoidal voltages of different frequencies, so it has the problems of large circuit and complicated control.

However, there is still a need for further improvement in the related art of DC-AC power conversion of the aforementioned publications No. I327812, No. I363464 and No. I462457. The foregoing China Patent is only a reference to the technical background of the present invention and the state of the art is not intended to limit the scope of the present invention.

In view of the above, the present invention provides a three-turn DC-AC power conversion device and a control method thereof, including a first T-type power electronic arm, a second T-type power electronic arm, and a capacitor. An arm, a filter inductor group, a decoupling circuit, a first filter capacitor, a second filter capacitor and a controller, and the three-turn DC-AC power conversion device has a constant current, a first AC 埠 and a second AC 埠, and the decoupling circuit is configured to decouple the different frequency AC component currents of the first T-type power electronic arm and the second T-type power electronic arm, so that only one set of power converters is needed Two kinds of AC sinusoidal voltages are used to greatly simplify the power circuit and control circuit.

The main purpose of the preferred embodiment of the present invention is to provide a three-turn DC-AC power conversion device and a control method thereof, including a first T-type power electronic arm, a second T-type power electronic arm, and a capacitor arm. a filter inductor group, a decoupling circuit, a first filter capacitor, a second filter capacitor and a controller, and the three-turn DC-AC power conversion device has a current flow, a first AC switch, and a first The AC coupling circuit is configured to decouple the AC component currents of the different frequencies of the first T-type power electronic arm and the second T-type power electronic arm to achieve the purpose of simplifying the overall circuit.

In order to achieve the above object, the third embodiment of the preferred embodiment of the present invention The DC-AC power conversion device comprises: a first T-type power electronic arm comprising a plurality of first power electronic switches, and the three-turn DC-AC power conversion device has a constant current, a first alternating current and a second AC power electronic arm, comprising a plurality of second power electronic switches, and the second T-type power electronic arm is connected to the first T-type power electronic arm to form a double T Type power electronic arm; a capacitor arm comprising two capacitors connected in series, and the capacitor arm is connected to the current flowing, and the series connection points of the two capacitors provide a common point, and the DC is connected to the capacitor An arm is provided to provide a DC voltage; a filter inductor group is coupled to an AC output terminal of the dual T-type power electronic arm; and a decoupling circuit is coupled to the dual T-type power electronic arm via the filter inductor group, And the decoupling circuit is configured to decouple the different frequency AC component currents of the first T-type power electronic arm and the second T-type power electronic arm; a first filter capacitor connected in parallel to the first AC port, and the first One The wave capacitor is connected to the double T-type power electronic arm via the filter inductor group; a second filter capacitor is connected in parallel to the second AC clamp, and the second filter capacitor is connected to the second filter capacitor via the decoupling circuit and the filter inductor group a dual T-type power electronic arm and a common point of the capacitor arm; and a controller for controlling a plurality of the first power electronic switch and the second T-type power electronic arm of the first T-type power electronic arm a second power electronic switch; wherein the first AC 提供 provides a first frequency AC sine wave voltage via the first filter capacitor, and the second AC 提供 provides a second frequency AC sine wave voltage via the second filter capacitor.

In order to achieve the above object, a control method for a three-turn DC-AC power conversion device according to a preferred embodiment of the present invention includes: providing a first T-type power electronic arm, a second T-type power electronic arm, a capacitor arm, and a a filter inductor group, a decoupling circuit, a first filter capacitor, a second filter capacitor and a controller, and the first T-type power electronic arm includes a plurality of first power electronic switches, and the second T-type power The electronic arm includes a plurality of second power electronic switches, and the second T-type power electronic arm is coupled to the first T-type power electronic arm to form a double T-type power electronic arm, and the capacitive arm includes two capacitors connected in series Connecting, connecting the capacitor arm to the current flowing, and the series connection point of the two capacitors provides a common point, and the three-turn DC-AC power conversion device has a constant current, a first alternating current, and a first Dielectric 埠, and the DC 埠 is connected to the capacitor arm to provide a DC voltage; the filter inductor group is connected to one of the dual T-type power electronic arms, and the decoupling circuit is connected The filter inductor group is connected to the dual T-type power electronic arm, and the decoupling circuit is configured to decouple different frequency AC component currents of the first T-type power electronic arm and the second T-type power electronic arm; a filter capacitor is connected in parallel to the first AC port, and the first filter capacitor is connected to the double T-type power electronic arm via the filter inductor group, and the second filter capacitor is connected in parallel to the second AC port, and the second a filter capacitor is connected to the dual T-type power electronic arm and the common point of the capacitor arm via the decoupling circuit and the filter inductor group; and the first power electronic switch of the first T-type power electronic arm is controlled by the controller a plurality of second power electronic switches of the second T-type power electronic arm; and providing a first frequency alternating current sine wave voltage via the first alternating current capacitor by using a first alternating current capacitor, and using the second alternating current 埠 via the second The filter capacitor provides a second frequency alternating sine wave voltage.

In the preferred embodiment of the invention, the first power electronic switch is four power electronic switches, and the second power electronic switch is four power electronic switches.

In the preferred embodiment of the present invention, the filter inductor group includes a first filter inductor and a second filter inductor.

In the preferred embodiment of the present invention, the decoupling circuit is a transformer or a transformer having the same number of turns on the primary side and the secondary side.

In the preferred embodiment of the present invention, the first frequency AC sine wave voltage is a 50 Hz AC sine wave voltage, and the second frequency AC sine wave voltage is a 60 Hz AC sine wave voltage.

1‧‧‧Double T-type power electronic arm

11‧‧‧First T-type power electronic arm

12‧‧‧Second T-type power electronic arm

100‧‧‧capacitor arm

101‧‧‧DC埠

102‧‧‧First Exchange

103‧‧‧Second exchange

2‧‧‧Filter inductor group

3‧‧‧Decoupling circuit

41‧‧‧First filter capacitor

42‧‧‧Second filter capacitor

5‧‧‧ Controller

FIG. 1 is a schematic diagram showing the circuit structure of a three-turn DC-AC power conversion device according to a preferred embodiment of the present invention.

Fig. 2 is a block diagram showing the current direction of a three-turn DC-AC power conversion device according to a preferred embodiment of the present invention.

Fig. 3(A) is a view showing a differential mode equivalent circuit of a three-turn DC-AC power conversion device according to a preferred embodiment of the present invention.

Fig. 3(B) is a view showing a common mode equivalent circuit of a three-turn DC-AC power conversion device according to a preferred embodiment of the present invention.

In order to fully understand the present invention, the preferred embodiments of the present invention are described in detail below, and are not intended to limit the invention.

The three-turn DC-AC power conversion device and the control method thereof according to the preferred embodiment of the present invention are applicable to various DC/AC power conversion devices, but are not intended to limit the scope of the present invention. In addition, the three-turn DC-AC power conversion device of the preferred embodiment of the present invention is suitable for use in a single group of DC power supply circuits and various power distribution systems.

Figure 1 discloses a three-turn DC in accordance with a preferred embodiment of the present invention - Schematic diagram of the circuit structure of the AC power conversion device. Referring to FIG. 1 , for example, a three-turn DC-AC power conversion device according to a preferred embodiment of the present invention includes a first T-type power electronic arm 11 , a second T-type power electronic arm 12 , and a first T-type power electronic arm 11 . The capacitor arm 100, a filter inductor group 2, a decoupling circuit 3, a first filter capacitor 41, a second filter capacitor 42 and a controller 5.

Referring to FIG. 1 again, the three-turn DC-AC power conversion device of the preferred embodiment of the present invention has a flow 101 (as shown on the left side of FIG. 1) and a first AC port 102 (eg, 1 is shown on the upper right side of the figure and a second AC port 103 (shown on the lower right side of FIG. 1) to form a three-turn DC-AC power conversion device.

Referring again to FIG. 1 , for example, the first T-type power electronic arm 11 includes a plurality of first power electronic switches (eg, S ₁ , S ₂ , S _1n , S _2n or other suitable amount of power). The switch], and the second T-type power electronic arm 12 also includes a plurality of second power electronic switches (eg, S ₃ , S ₄ , S _3n , S _4n or other suitable number of power switches). In addition, the capacitor arm 100 includes a first DC capacitor C ₁ and a second DC capacitor C ₂ , and the series connection points of the first DC capacitor C ₁ and the second DC capacitor C ₂ are a common point, and the A DC port 101 is coupled to the capacitive arm 100 to provide a DC voltage.

Referring to FIG. 1 again, for example, the filter inductor group 2 includes a first filter inductor L ₁ and a second filter inductor L ₂ , and the first filter inductor L ₁ and a second The filter inductor L _{2 is} electrically connected between the AC output end of the double T-type power electronic arm 1 and the decoupling circuit 3. The filter inductor group 2 is configured to filter out the switching of the first power electronic switch [S ₁ , S ₂ , S _1n , S _2n ] and the second power electronic switch [S ₃ , S ₄ , S _3n , S _4n ] High frequency harmonic current.

Referring to FIG. 1 again, for example, the decoupling circuit 3 can be selected as a transformer having the same number of turns on the primary side and the secondary side. In addition, the decoupling circuit 3 is connected to the AC output end of the dual T-type power electronic arm 1 via the filter inductor group 2, and the decoupling circuit 3 is used to decoupling the first T-type power electronic arm 11 and a second T-type components of different frequency alternating current power electronics of arm 12 [] i ₁ and i _2, i.e. comprising a differential mode] [differential mode and common mode current component [component] common mode current.

Referring to FIG. 1 again, for example, the first filter capacitor 41 can be selected as a first frequency filter capacitor (eg, 50 Hz or other suitable frequency), and the first filter capacitor 41 is connected in parallel with the first AC 埠 102, and the first filter capacitor 41 is connected to one of the double T-type power electronic arm 1 via the filter inductor group 2 to decouple the first T-type power electronic with the decoupling circuit 3 The differential mode component current of the arm 11 and the second T-type power electronic arm 12 establishes the first frequency AC sinusoidal voltage.

Referring to FIG. 1 again, for example, the second filter capacitor 42 can be selected as a second frequency filter capacitor (eg, 60 Hz or other suitable frequency), and the second filter capacitor 42 is connected in parallel with the first An AC 埠 103, and the second filter capacitor 42 is connected to the second T-type power electronic arm 12 of the double T-type power electronic arm 1 via the decoupling circuit 3 and the filter inductor group 2, so as to utilize the decoupling circuit 3 Decoupling the common mode component currents of the first T-type power electronic arm 11 and the second T-type power electronic arm 12 establishes the second frequency AC sine wave voltage.

Referring to FIG. 1 again, for example, the controller 5 is configured to control a plurality of first power electronic switches [S ₁ , S ₂ , S _1n , S _{2n for} operating the first T-type power electronic arm 11 . And opening and closing of the plurality of second power electronic switches [S ₃ , S ₄ , S _3n , S _4n ] of the second T-type power electronic arm 12 as shown in the lower part of FIG. 1 . Thus, the differential mode component and the total are generated by the switching manner of the first power electronic switch [S ₁ , S ₂ , S _1n , S _2n ] and the second power electronic switch [S ₃ , S ₄ , S _3n , S _4n ] The current of the mode component.

Referring to FIG. 1 again, for example, the first AC port 102 provides a first frequency AC sinusoidal voltage via the first filter capacitor 41 (eg, 50 Hz or other suitable frequency AC sine wave voltage). Used to a first load, and at the same time the second AC 埠 103 provides a second frequency AC sine wave voltage (eg, 60 Hz or other suitable frequency AC sine wave voltage) to the second load via the second filter capacitor 42 use.

Fig. 2 is a block diagram showing the current direction of a three-turn DC-AC power conversion device according to a preferred embodiment of the present invention, which corresponds to Fig. 1. Referring to Figures 1 and 2, the formulas of the alternating current component currents [ i ₁ ] and [ i ₂ ] of the first T-type power electronic arm 11 and the second T-type power electronic arm 12 are as follows: i ₁ = i _{d 1} + i _{c 1} (1)

i ₂ = i _{d 2} + i _{c 2} (2)

According to the common mode and differential mode signal analysis theory of conducted electromagnetic interference, formulas (1) and (2) can be divided into differential mode components [ i _d1 and i _d2 ] and common mode components [ i _c1 and i _c2 ]. The formula is as follows: i _{d 1} =- i _{d 2} (3)

i _{c 1} = i _{c 2} (4)

The two currents of the differential mode component have the same magnitude, but the opposite directions are as shown in the formula (3); and the two currents of the common mode component have the same magnitude and direction, as shown in the formula (4).

Please refer to FIG 1 and FIG 2, the first T-shaped arm 11 of the power electronics output current I _[1] and a second T-type electronic power arm 12 of the output current i ₂ [] for the decoupling circuit 3 via After decoupling, a differential mode component current [ i _diff , for example, a 50 Hz AC sine wave voltage] and a common mode component current [ i _com , for example, a 60 Hz AC sine wave voltage) are obtained. The differential mode current [ i _diff ] and the common mode current [ i _com ] can be expressed as follows: i _diff = i _{d 1} =- i _{d 2} (5)

i _com = i _{c 1} + i _{c 2} (6)

Referring to Figures 1 and 2 again, according to equations (5) and (6), the currents supplied to the first AC port 102 and the second AC port 103 can be expressed as follows: i _AC50Hz = i _diff - i _{cf 1} (7)

i _AC60Hz =i _com - i _{cf 2} (8)

Where i _{AC50Hz is} the current of the first AC port 102, and i _{AC60Hz is} the current of the second AC port 103.

Fig. 3(A) is a view showing a differential-mode equivalent circuit of a three-turn DC-AC power conversion device according to a preferred embodiment of the present invention. Referring to the first, second, and third (A) diagrams, based on the transformer theory, the current of the primary side and the secondary side (black point end) of the transformer of the decoupling circuit 3 must present a corresponding condition of one input and one output, then The differential mode current cannot flow into the decoupling circuit 3 [transformer] due to the configuration of the decoupling circuit 3. Therefore, the decoupling circuit 3 [transformer circuit] will be opened in the differential mode equivalent circuit as shown in Fig. 3(A). The terminal voltages v _T1.d and v _{T2.d of the} decoupling circuit 3 [transformer] can be expressed as follows: v _{T 1. d} = v _{T 2. d} = v _{AC 50 Hz} /2 (9)

Where v _{AC50Hz is} the voltage of the first AC port 102.

Fig. 3(B) is a view showing a common-mode equivalent circuit of a three-turn DC-AC power conversion device according to a preferred embodiment of the present invention, which is referred to Fig. 3(A) for comparison. Referring to Figures 1, 2, and 3(B), since the common mode components [ i _c1 and i _c2 ] are the same in size and direction, i _c1 passes through the primary side of the decoupling circuit 3 [transformer] [black dots] The end] flows in, and i _c2 flows out via the secondary side (black point end) of the decoupling circuit 3 [transformer], and i _c1 and i _c2 output the decoupling circuit 3 and combine them into a common mode current i _com . If the leakage inductance of the transformer is not considered, the terminal voltages v _T1.C and v _{T2.C of the} decoupling circuit 3 [transformer] are all zero. According to the overlap theorem, the decoupling circuit 3 [transformer] current flowing through the primary side and the secondary side winding can be expressed as follows: i _c1 = i _c2 = i _com /2 (10)

Referring to Figures 1, 2, and 3 (B), the terminal voltage of the decoupling circuit 3 [transformer] has only the voltage component of the first AC 埠 102, and the current of the primary side and the secondary winding. Only the common mode current component flows, so the current components of different frequencies can be decoupled. It can be seen from Fig. 1 that the system real work relationship can be expressed as follows: P _DC = P _{AC 50 Hz} + P _{AC 60 Hz} + P _loss (11)

The P _DC is the real power provided by the DC power source, P _{AC50Hz is} the real power of the first AC _埠 102 to the load output, P _{AC60Hz is} the real power of the second AC _埠 103 to the load output , and P _loss is the power converter. The real power of the loss.

In addition, the 50 Hz AC _埠 voltage v _{AC 50 Hz} and 60 Hz AC _埠 v AC 60 Hz can be expressed as follows: v _AC50Hz = i _AC50Hz × z _{AC 50 Hz} = i _{cf 1} × z _{cf 1} = i _diff × ( z _{AC 50 Hz} // z _{cf 1} ) (12)

v _AC60Hz =i _AC60Hz × z _{AC 60 Hz} = i _{cf 2} × z _{cf 2} = i _com ×( z _{AC 60 Hz} // z _{cf 2} ) (13)

Wherein z _AC50Hz and z _AC60Hz are respectively the load impedance of the first AC port 102 and the load impedance connected to the second AC port 103; z _cf1 and z _cf2 are respectively the first filter capacitor 41 and the second filter Capacitance of capacitor 42.

Under the leakage inductance of the transformer, the v _AC60Hz and v _AC50Hz can be controlled by the common mode and differential mode currents i _com and i _diff respectively. The formulas of the different frequency AC component currents [ i ₁ ] and [ i ₂ ] of the first T-type power electronic arm 11 and the second T-type power electronic arm 12 are as follows:

The output currents of the first T-type power electronic arm 11 and the second T-type power electronic arm 12 can be controlled by the above formulas (14) and (15). The three-turn DC-AC power conversion device of the invention can achieve the function of simultaneously outputting two different frequency AC voltages.

The foregoing preferred embodiments are merely illustrative of the invention and the technical features thereof, and the techniques of the embodiments can be carried out with various substantial equivalent modifications and/or alternatives; therefore, the scope of the invention is subject to the appended claims. The scope defined by the scope shall prevail. The copyright limitation of this case is used for the purpose of patent application in the Republic of China.

Claims (10)

A three-turn DC-AC power conversion device includes: a first T-type power electronic arm including a plurality of first power electronic switches, and the three-turn DC-AC power conversion device has a flow, a a first alternating current port and a second alternating current port; a second T-type power electronic arm comprising a plurality of second power electronic switches, wherein the second T-type power electronic arm is coupled to the first T-type power electronic arm, To form a pair of T-type power electronic arm; a capacitor arm comprising two capacitors connected in series, and the capacitor arm is connected to the current flowing, and the series connection points of the two capacitors provide a common point, and the DC is utilized埠 is connected to the capacitor arm to provide a DC voltage; a filter inductor group is connected to one of the AC output terminals of the dual T-type power electronic arm; and a decoupling circuit is connected to the double T via the filter inductor group a power electronic arm, and the decoupling circuit is configured to decouple different frequency AC component currents of the first T-type power electronic arm and the second T-type power electronic arm; a first filter capacitor connected in parallel to the first AC And the first filter capacitor is connected to the double T-type power electronic arm via the filter inductor group and the decoupling circuit; a second filter capacitor is connected in parallel to the second AC埠, and the second filter capacitor is connected to the second AC capacitor a coupling circuit and a filter inductor group are connected to the common point of the double T-type power electronic arm and the capacitor arm; and a controller for controlling the first power electronic switch and the first power electronic arm of the first T-type power electronic arm a plurality of second power electronic switches of the two T-type power electronic arm; wherein the three-turn DC-AC power conversion device has a continuous flow, a first alternating current, and a second alternating current, and the first alternating current The first filter capacitor provides a first frequency AC sine wave voltage, and the second AC coil provides a second frequency AC sine wave voltage via the second filter capacitor. The three-wire DC-AC power conversion device according to claim 1, wherein the first power electronic switch is four power electronic switches, and the second power electronic switch is four power electronic switches. The three-turn DC-AC power conversion device according to claim 1, wherein the filter inductor group comprises a first filter inductor and a second filter inductor. The three-turn DC-AC power conversion device according to Item 1 of the patent application scope, wherein the decoupling circuit is a transformer or a transformer having the same number of turns on the primary side and the secondary side. According to the three-way DC-AC power conversion device described in claim 1, wherein the first frequency AC sine wave voltage is a 50 Hz AC sine wave voltage, and the second frequency AC sine wave voltage is a 60 Hz AC sine wave Voltage. A control method for a three-turn DC-AC power conversion device, comprising: providing a first T-type power electronic arm, a second T-type power electronic arm, a filter inductor group, a decoupling circuit, and a first filter a capacitor, a second filter capacitor, and a controller, wherein the first T-type power electronic arm includes a plurality of first power electronic switches, and the second T-type power electronic arm includes a plurality of second power electronic switches, and the a second T-type power electronic arm is coupled to the first T-type power electronic arm to form a double T-type power electronic arm, and the capacitive arm includes two capacitors connected in series, the capacitive arm is connected to the current flowing, and The series connection point of the two capacitors provides a common point, and the three-turn DC-AC power conversion device has a current flowing, a first alternating current, and a second alternating current, and is connected to the capacitor by using the direct current An arm is provided to provide a DC voltage; the filter inductor group is coupled to an AC output terminal of the dual T-type power electronic arm, and the decoupling circuit is coupled to the dual T-type power electronic arm via the filter inductor group, The decoupling circuit for decoupling the different frequencies of the T-shaped first arm and the second power electronics arm of the T-shaped electronic component AC electrical power a first filter capacitor is connected in parallel to the first AC buffer, and the first filter capacitor is connected to the double T-type power electronic arm via the filter inductor group, and the second filter capacitor is connected in parallel to the second AC埠, and the second filter capacitor is connected to the common point of the dual T-type power electronic arm and the capacitor arm via the decoupling circuit and the filter inductor group; and the controller controls the plurality of first T-type power electronic arms a plurality of second power electronic switches of the first power electronic switch and the second T-type power electronic arm; and providing a first frequency alternating current sinusoidal voltage via the first alternating current capacitor by using a first alternating current capacitor, and using a second The AC 提供 provides a second frequency AC sine wave voltage via the second filter capacitor. According to the control method of the three-turn DC-AC power conversion device described in claim 6, wherein the first power electronic switch is four power electronic switches, and the second power electronic switch is four power electronic switches . The control method of the three-turn DC-AC power conversion device according to the sixth aspect of the patent application, wherein the filter inductor group comprises a first filter inductor and a second filter inductor. The control method of the three-turn DC-AC power conversion device according to Item 6 of the patent application scope, wherein the decoupling circuit is a transformer or a transformer having the same number of turns on the primary side and the secondary side. According to the control method of the three-turn DC-AC power conversion device described in claim 6, wherein the first frequency AC sine wave voltage is a 50 Hz AC sine wave voltage, and the second frequency AC sine wave voltage is 60 Hz. AC sine wave voltage.