CN115833613A - Alternating current converter for improving output gain and design method thereof - Google Patents
Alternating current converter for improving output gain and design method thereof Download PDFInfo
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Abstract
The invention discloses an alternating current converter for improving output gain and a design method thereof, relates to the technical field of alternating current power converters, solves the problems of complex structure control and low gain of the existing alternating current converter, and has the technical scheme key points that: embedding a right-angle transformer coupling structure in the alternating current chopper circuit to form a right-angle magnetic coupling network alternating current converter; an inductor L and a capacitor C are introduced into the input end of the right-angle magnetic coupling network alternating current converter 1 Or introducing a capacitance C 1 Forming a quasi Z source network alternating current converter; leading a switch in the quasi Z source network alternating current converter to form an improved quasi Z source network alternating current converter; introducing a voltage-multiplying capacitor C into the improved quasi-Z source network alternating-current converter c Forming an enhanced AC converter; the alternating current converter reserves the advantages of simple structure, small volume and simple and convenient control logic of the alternating current chopper circuit, and the input and output are connected with the common ground, so that the voltage gain is improved.
Description
Technical Field
The invention relates to the technical field of alternating current power converters, in particular to an alternating current converter for improving output gain and a design method thereof.
Background
In the existing alternating current conversion technology, an indirect alternating current converter and a direct alternating current converter are included, and at present, the alternating current converter either needs a complex structure and volume and needs complex control logic; or the voltage conversion gain is low, so that the energy conversion efficiency of the input and the output is low. Due to the limitations of the two aspects, the development of the traditional alternating current converter cannot break through the technical bottleneck, and the realization of the system function cannot be met. Therefore, there is a need for a method for designing an ac converter, which is a series of ac converters with simple structure, convenient control and high gain.
Disclosure of Invention
The invention aims to provide an alternating current converter for improving output gain and a design method thereof, which solve the problems of complex structure, complex control logic and lower gain of the existing alternating current converter.
The first aspect of the present invention provides a method for designing an ac converter for increasing output gain, where the above technical objective is achieved by the following technical solutions: comprises that
S1, embedding a right-angle transformer coupling structure in an alternating current chopper circuit to form a right-angle magnetic coupling network alternating current converter;
s2, introducing an inductor L and a capacitor C into the input end of the right-angle magnetic coupling network alternating current converter 1 Or introducing a capacitance C 1 Forming a quasi Z source network alternating current converter;
s3, leading a switch in the quasi Z source network alternating current converter to form an improved quasi Z source network alternating current converter;
s4, introducing a voltage-multiplying capacitor C into the improved quasi-Z source network alternating-current converter c Form an increaseA robust AC converter.
By adopting the technical scheme, in the step S1, the right-angle transformer coupling structure is used as a coupling energy storage inductor to be embedded into the alternating current chopper circuit to form the alternating current converter, and when the alternating current chopper circuit is used, voltage conversion can be realized through switch PWM control, so that the advantages of simple structure, small volume and simple and convenient control logic of the alternating current chopper circuit are reserved; in the step S2, an inductor L and a capacitor C1 are introduced as energy storage elements, so that the voltage gain of the ac converter is further improved, and the electromagnetic compatibility of the power module is improved by smoothly inputting current through the inductor L; in step S3, the switch is arranged in front, so that the loss and the stress of a switch tube in the alternating current converter are reduced, and the efficiency of the alternating current converter is further improved; finally, in step S4, a voltage-multiplying capacitor C is introduced c And the small-size and high-efficiency design of the alternating current converter is realized.
The second aspect of the present invention provides an ac converter for increasing output gain, and the above technical object is achieved by the following technical solutions: comprises an AC power supply V in A first bidirectional switch S a A second bidirectional switch S b A transformer coupling structure N, a capacitor C and an inductor L 0 Capacitor C 0 And a load R, the AC power supply V in Through a first bidirectional switch S a A transformer coupling structure N, a capacitor C and the AC power supply V in Is connected to the second terminal of the transformer coupling structure N via a second bidirectional switch S b And the AC power supply V in The second end of the transformer coupling structure N is connected with the first end of the transformer coupling structure N through an inductor L 0 Capacitor C 0 And the AC power supply V in Is connected to the second terminal of the capacitor C 0 In parallel with the load R.
By adopting the technical scheme, the right-angle transformer coupling structure is embedded into the alternating current chopper circuit as a coupling energy storage inductor to form the alternating current converter, when the direct current transformer is used, voltage conversion can be realized through switch PWM control, the advantages of simple structure, small size and simple and convenient control logic of the alternating current chopper circuit are reserved, the input and output of the alternating current converter are grounded, the interference from a ground wire is filtered, and the voltage gain is improved.
The third aspect of the present invention provides an ac converter for increasing output gain, and the above technical object is achieved by the following technical solutions: comprises an AC power supply V in The first two-way switch S a A second bidirectional switch S b A transformer coupling structure N, a capacitor C and an inductor L 0 Capacitor C 0 Load R, inductor L and capacitor C 1 Said AC power supply V in Through an inductor L and a first bidirectional switch S a A transformer coupling structure N, a capacitor C and the AC power supply V in Is connected to the second terminal of the first bidirectional switch S a Through a capacitor C 1 The second end of the transformer coupling structure N is connected with the second end of the transformer coupling structure N through a second bidirectional switch S b And the AC power supply V in The second end of the transformer coupling structure N is connected with the first end of the transformer coupling structure N through an inductor L 0 Capacitor C 0 And the AC power supply V in Is connected to the second terminal of the capacitor C 0 In parallel with the load R.
By adopting the technical scheme, the inductor L and the capacitor C are introduced on the basis of the alternating current converter formed by the coupling junction of the alternating current chopper circuit and the transformer 1 As the energy storage element, the voltage gain of the alternating current converter is further improved, and the input current is smoothed through the inductor L, so that the electromagnetic compatibility characteristic of the alternating current converter is improved.
A fourth aspect of the present invention provides an ac converter for increasing output gain, where the technical purpose is achieved by the following technical solutions: comprises an AC power supply V in The first two-way switch S a A second bidirectional switch S b A transformer coupling structure N, a capacitor C and an inductor L 0 Capacitor C 0 A load R and a capacitor C 1 Said AC power supply V in Through a first bidirectional switch S a A transformer coupling structure N, a capacitor C and the AC power supply V in Is connected to the second terminal of the first bidirectional switch S a Through a capacitor C 1 Is coupled with the transformerThe third end of the combined structure N is connected, and the second end of the transformer coupled structure N passes through the second bidirectional switch S b And the AC power supply V in The second end of the transformer coupling structure N is connected with the first end of the transformer coupling structure N through an inductor L 0 Capacitor C 0 And the AC power supply V in To the second terminal of said capacitor C 0 In parallel with the load R.
By adopting the technical scheme, the capacitor C is introduced on the basis of the alternating current converter formed by the coupling junction of the alternating current chopper circuit and the transformer 1 The voltage gain of the ac converter is further improved as an energy storage element.
The fifth aspect of the present invention provides an ac converter for increasing output gain, and the above technical object is achieved by the following technical solutions: comprises an AC power supply V in The first two-way switch S a A second bidirectional switch S b Transformer coupling structure N, capacitor C 0 Load R, inductor L and capacitor C 1 Said AC power supply V in Through an inductor L and a capacitor C 1 Transformer coupling structure N, second bidirectional switch S b And the AC power supply V in Is connected to the second terminal of the capacitor C 1 Through a first bidirectional switch S a The second end of the transformer coupling structure N is connected with the second end of the transformer coupling structure N through a capacitor C 0 And the AC power supply V in Is connected to the second terminal of the capacitor C 0 In parallel with the load R.
By adopting the technical scheme, the inductor L and the capacitor C are introduced 1 On the basis of being used as an energy storage element, the switch is arranged in front, so that the loss and the stress of the switch in the alternating current converter are reduced, and the efficiency of the alternating current converter is further improved.
A sixth aspect of the present invention provides an ac converter for increasing output gain, wherein the technical purpose is achieved by the following technical solutions: comprises an AC power supply V in The first two-way switch S a A second bidirectional switch S b Transformer coupling structure N, capacitor C 0 A load R, an inductor L, a capacitor C1,Voltage-multiplying capacitor C c And a third bidirectional switch S c Said AC power supply V in A first end of the first bi-directional switch is connected with a first bi-directional switch S through a transformer coupling structure N a And the AC power supply V in Is connected to the second terminal of the transformer coupling structure N, the third terminal of the transformer coupling structure N is connected to the second terminal of the transformer coupling structure N via a second switch S b Voltage-multiplying capacitor C c And the AC power supply V in The second end of the transformer coupling structure N is connected with the first end of the transformer coupling structure through a capacitor C 1 A third two-way switch S c And the voltage-multiplying capacitor C c Is connected to the first terminal of the capacitor C 1 A second terminal of the filter is connected with an inductor L and a filter capacitor C 0 And the AC power supply V in Is connected with the second end of the filter capacitor C, the load R is connected with the filter capacitor C 0 And (4) connecting in parallel.
By adopting the technical scheme, the voltage-multiplying capacitor C is introduced on the basis of the preposed switch c The output gain of the alternating current converter is improved, and the small-size and high-efficiency design of the alternating current converter is realized.
Further, the transformer coupling structure N is composed of two or three coupling inductors.
Furthermore, the two coupling inductors form a T-shaped coupling structure, a Gamma-shaped coupling structure or an inverse Gamma-shaped coupling structure;
in the T-shaped coupling structure, a synonym end of a first coupling inductor is connected with a synonym end of a second inductor, the synonym end of the first coupling inductor is used as a first end of the transformer coupling structure, the synonym end of the first coupling inductor is used as a third end of the transformer coupling structure, and the synonym end of the second coupling inductor is used as a second end of the transformer coupling structure;
in the Gamma type coupling structure, a homonymous end of a first coupling inductor is connected with a homonymous end of a second inductor, the homonymous end of the first coupling inductor is used as a first end of a transformer coupling structure, a synonym end of the first coupling inductor is used as a second end of the transformer coupling structure, and the synonym end of the second coupling inductor is used as a third end of the transformer coupling structure;
in the inverse Gamma type coupling structure, a synonym end of a first coupling inductor is connected with a synonym end of a second inductor, the synonym end of the first coupling inductor is used as a first end of the transformer coupling structure, the synonym end of the first coupling inductor is used as a second end of the transformer coupling structure, and the synonym end of the second coupling inductor is used as a third end of the transformer coupling structure.
Furthermore, the three coupling inductors form a Y-shaped coupling structure; in the Y-shaped coupling structure, a synonym end of a first coupling inductor, a synonym end of a second coupling inductor and a synonym end of a third coupling inductor are connected in common, the synonym end of the first coupling inductor is used as a first end of the transformer coupling structure, the synonym end of the third coupling inductor is used as a second end of the transformer coupling structure, and the synonym end of the third coupling inductor is used as a third end of the transformer coupling structure.
Further, the first bidirectional switch S a And a second bidirectional switch S b Each of the two MOS tubes is composed of two MOS tubes which are connected in reverse.
Compared with the prior art, the method has the following beneficial effects: the application provides an alternating current converter design method for improving output gain and a series of alternating current converters designed in the implementation process of the method, based on the idea that an alternating current chopper circuit and a transformer coupling structure are combined, the alternating current converter can obviously improve the output voltage gain, improve the efficiency of the alternating current converter and meet the requirement of reducing the voltage stress of a switching tube. In addition, the common-mode inductor is not required to be connected into the alternating-current converter to optimize electromagnetic compatibility RE102, input current can still be smoothed through the input end inductor L, and power grid pollution caused by input current harmonic waves is reduced.
Drawings
The accompanying drawings, which are included to provide a further understanding of the embodiments of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principles of the invention. In the drawings:
FIG. 1 is a schematic diagram of an AC chopper circuit provided in accordance with the present invention;
FIG. 2 is a schematic diagram of a transformer coupling structure according to the present invention
Fig. 3 is a flowchart of a method for designing an ac converter according to embodiment 1 of the present invention;
fig. 4 is a schematic diagram of a right-angle magnetic coupling network ac converter provided in embodiment 2 of the present invention;
fig. 5 is a schematic diagram of an a-type quasi-Z source network ac converter provided in embodiment 3 of the present invention;
fig. 6 is a schematic diagram of a type b quasi Z source network ac converter according to embodiment 4 of the present invention;
fig. 7 is a schematic diagram of an improved Z-source network ac converter provided in embodiment 5 of the present invention;
FIG. 8 is a schematic diagram of an enhanced AC converter provided in embodiment 6 of the present invention;
fig. 9 is an equivalent circuit diagram of a right-angle magnetic coupling network ac converter according to embodiment 2 of the present invention;
fig. 10 is a diagram for analyzing the switching operation of the enhanced ac converter according to embodiment 6 of the present invention;
fig. 11 is an equivalent circuit diagram of two modes of the enhanced Y-source high-gain AC-AC converter provided in embodiment 6 of the present invention.
Detailed Description
Hereinafter, the terms "includes" or "may include" used in various embodiments of the present invention indicate the presence of the claimed function, operation, or element, and do not limit the addition of one or more functions, operations, or elements. Furthermore, as used in various embodiments of the present invention, the terms "comprises," "comprising," "includes," "including," "has," "having" and their derivatives are intended to mean that the specified features, numbers, steps, operations, elements, components, or combinations of the foregoing, are only meant to indicate that a particular feature, number, step, operation, element, component, or combination of the foregoing, and should not be construed as first excluding the existence of, or adding to the possibility of, one or more other features, numbers, steps, operations, elements, components, or combinations of the foregoing.
In various embodiments of the invention, the expression "or" at least one of B or/and C "includes any or all combinations of the words listed simultaneously. For example, the expression "B or C" or "at least one of B or/and C" may include B, may include C, or may include both B and C.
Expressions (such as "first", "second", and the like) used in various embodiments of the present invention may modify various constituent elements in various embodiments, but may not limit the respective constituent elements. For example, the above description does not limit the order and/or importance of the elements described. The above description is only intended to distinguish one element from another. For example, the first user device and the second user device indicate different user devices, although both are user devices. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, without departing from the scope of various embodiments of the present invention.
It should be noted that: if it is described that one constituent element is "connected" to or "connected" with another constituent element, the first constituent element may be directly connected to the second constituent element, and the third constituent element may be "connected" between the first constituent element and the second constituent element. In contrast, when one constituent element is "directly connected" to or with another constituent element, it is understood that there is no third constituent element between the first constituent element and the second constituent element.
The terminology used in the various embodiments of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the various embodiments of the invention. As used herein, the singular forms are intended to include the plural forms as well, unless the context clearly indicates otherwise. Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which various embodiments of the present invention belong. The terms (such as those defined in commonly used dictionaries) should be interpreted as having a meaning that is consistent with their contextual meaning in the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein in various embodiments of the present invention.
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to examples and accompanying drawings, and the exemplary embodiments and descriptions thereof are only used for explaining the present invention and are not meant to limit the present invention.
Referring to fig. 1, fig. 1 is a schematic diagram of an ac chopper circuit, which includes: a first bidirectional switch S a A second bidirectional switch S b Inductor L 0 Capacitor C 0 And a load R; in ideal chopping mode, two bidirectional switches work alternately to modulate the voltage applied to the load, and the inductor L 0 And a capacitor C 0 Forming a filter circuit.
Referring to fig. 2, fig. 2 is a schematic diagram of a transformer coupling structure, where the transformer coupling structure is a right-angle transformer coupling structure, specifically, the transformer coupling structure N is composed of two or three coupling inductors, two of the coupling inductors form a T-type coupling structure, a Gamma-type coupling structure, or a reverse Gamma-type coupling structure, and three of the coupling inductors form a Y-type coupling structure.
Referring to fig. 2 (a), in the Y-type coupling structure, a different-name end of the first coupling inductor, a same-name end of the second coupling inductor, and a same-name end of the third coupling inductor are connected in common, the same-name end of the first coupling inductor is used as a first end of the transformer coupling structure, the different-name end of the third coupling inductor is used as a second end of the transformer coupling structure, and the different-name end of the third coupling inductor is used as a third end of the transformer coupling structure.
Referring to fig. 2 (b), in the Gamma-type coupling structure, a dotted terminal of a first coupling inductor is connected to a dotted terminal of a second inductor, the dotted terminal of the first coupling inductor is used as a first terminal of the transformer coupling structure, a dotted terminal of the first coupling inductor is used as a second terminal of the transformer coupling structure, and a dotted terminal of the second coupling inductor is used as a third terminal of the transformer coupling structure.
Referring to fig. 2 (c), in the T-shaped coupling structure, the synonym terminal of the first coupling inductor is connected to the synonym terminal of the second inductor, the synonym terminal of the first coupling inductor is used as the first terminal of the transformer coupling structure, the synonym terminal of the first coupling inductor is used as the third terminal of the transformer coupling structure, and the synonym terminal of the second coupling inductor is used as the second terminal of the transformer coupling structure.
Referring to fig. 2 (d), in the inverse Gamma-type coupling structure, the synonym terminal of the first coupling inductor is connected to the synonym terminal of the second inductor, the synonym terminal of the first coupling inductor is used as the first terminal of the transformer coupling structure, the synonym terminal of the first coupling inductor is used as the second terminal of the transformer coupling structure, and the synonym terminal of the second coupling inductor is used as the third terminal of the transformer coupling structure.
For convenience of description, in the following description, the left side/upper side of an element in a circuit diagram is regarded as a first end of the element, the right side/lower side of the element is regarded as a second end of the element, and for the transformer coupling structure N, the left side is the first end, the right side is the second end, and the lower side is the third end.
Example 1
The embodiment provides a method for designing an alternating current converter for improving output gain, wherein a right-angle transformer coupling structure is combined with an alternating current chopper circuit and is gradually improved to form a series of alternating current converters.
Referring to fig. 3, the method for designing an ac converter includes:
s1, embedding a right-angle transformer coupling structure in an alternating current chopper circuit to form a right-angle magnetic coupling network AC-AC power supply module;
s2, introducing an inductor L and a capacitor C into the input end of the right-angle magnetic coupling network AC-AC power supply module 1 Or introducing a capacitance C 1 Forming a quasi-Z source network power supply module;
s3, leading a switch in the quasi-Z source network power supply module to form an improved quasi-Z source network power supply module;
s4, introducing a voltage-multiplying capacitor C into the improved quasi-Z source network power supply module c And forming the enhanced power supply module.
The right-angle transformer coupling structure is used as a coupling energy storage inductor to be embedded into an alternating current chopper circuit to form an alternating current converter, when the converter is used, voltage conversion can be realized through switch PWM control, and the advantages of simple structure, small size and simple and convenient control logic of the alternating current chopper circuit are reserved; in the step S2, an inductor L and a capacitor C1 are introduced as energy storage elements, so that the voltage gain of the ac converter is further improved, and the electromagnetic compatibility of the power module is improved by smoothly inputting current through the inductor L; in step S3, the switch is arranged in front, so that the loss and the stress of a switch tube in the alternating current converter are reduced, and the efficiency of the alternating current converter is further improved; and finally, in the step S4, a voltage-multiplying capacitor is introduced, so that the small-size and high-efficiency design of the alternating current converter is realized.
Example 2
The embodiment provides an alternating current converter for improving output gain, and a right-angle magnetic coupling network alternating current converter is formed based on the idea of combining a right-angle transformer coupling structure and an alternating current chopper circuit.
Referring to fig. 4, the right-angle magnetic coupling network ac converter includes: AC power supply V in The first two-way switch S a A second bidirectional switch S b A transformer coupling structure N, a capacitor C and an inductor L 0 Capacitor C 0 And a load R, the AC power supply V in Through a first bidirectional switch S a A transformer coupling structure N, a capacitor C and the AC power supply V in Is connected to the second terminal of the transformer coupling structure N via a second bidirectional switch S b And the AC power supply V in The second end of the transformer coupling structure N is connected with the first end of the transformer coupling structure N through an inductor L 0 Capacitor C 0 And the AC power supply V in Is connected to the second terminal of the capacitor C 0 In parallel with the load R.
In a right-angle magnetic coupling network AC converter, a first bidirectional switch S a For chopping switches, second bidirectional switches S a For follow current switch, transformer coupling structure N is used for coupling energy storage, capacitor C is used for storing and boosting energy, and inductor L 0 Capacitor C 0 And a filter circuit is formed while energy is stored. A right-angle transformer coupling structure N is embedded in the AC chopper circuit, and the transformer coupling structure N, a capacitor C and an inductor L are connected with the transformer coupling structure N 0 And a capacitor C 0 Stored energy, inductance L 0 And filteringCapacitor C 0 The filter has a filtering function and supplies power to a load R; and the input and output of the alternating current converter are grounded in common, so that the alternating current converter is different from a common Z-source transformer structure, the interference from the ground wire is filtered, and the voltage gain is also improved.
The working principle and the parameter design process of the right-angle magnetic coupling network ac converter are explained in detail below. To facilitate the analysis of the topology, we make the following simplification: (1) All the energy storage elements are ideal energy storage elements, and the switching tube is an ideal switching tube; and (2) the circuit works in an inductive current continuous state. (3) The coupling coefficient of the coupling inductor can reach more than 0.99, so the transformer can be regarded as an ideal transformer. It should be noted that the description in this section about the operation principle of the converter is also applicable to the converters improved later, and therefore, the description of the converters improved later is not repeated. An equivalent circuit of the simplified rear-right-angle magnetic coupling network ac converter is shown in fig. 9 (a).
In each switching cycle, the circuit comprises two operating states, an input terminal conducting state and an input terminal non-conducting state. And when the switching period is T, DT is in a through state, and (1-D) T is in a non-through state.
Then, based on the above assumption, in the mode 1, the circuit mode is equivalent to that shown in fig. 9 (b), and under this mode, kirchhoff's law is written below, and the following equation holds:
the mode 2 of the circuit is shown in fig. 9 (c), and in this mode, the following equation holds according to kirchhoff's law:
under the steady state condition of one period, which can be obtained by volt-second balance and ampere-second balance, the circuit state satisfies the following equation:
the input-output equation can be solved, namely:
the voltage input-output ratio, i.e. the gain formula, can be seen from the above equation:
according to the formula, the converter can realize the voltage increase and decrease of the sine alternating-current voltage by adjusting the conduction duty ratio of the switching tube and the turn ratio of the transformer.
The following detailed description relates to the parametric design of the converter:
a. design of impedance source network parameters of transformer
When designing the impedance source network parameters, the inductance parameters in the network are designed by taking the current ripple passing through the inductor as the reference, and when the switch tube is conducted, the inductor L is connected M The voltage at two points is
At the moment, the inductor is required to meet the condition:
in addition, the inductance ripple satisfies the condition
Thus:
similarly, the capacitor parameter is designed based on the voltage ripple at two ends of the capacitor, and can be obtained as follows:
when a new converter topology is proposed in the rest chapters, converter parameters need to be designed, and the design mode is similar, so that the problem will not be described again.
b. Voltage current stress analysis
The voltage stress of the switching tube is the maximum voltage at two ends of the switching tube when the switching tube is in a disconnected state, and can be obtained as follows:
the voltage stress of the capacitor is the voltage across the capacitor, and can be obtained as follows:
the current stress of the switching tube is the maximum current flowing through the switching tube when the switching tube is in a conducting state, and can be obtained as follows:
c. converter output filter parameter design
The inductance of the output filter can be calculated as follows:
the output filter capacitance can be calculated by:
wherein f is c And R is the cut-off frequency and the load resistance value of the output waveform. ε may take a value between 0.5 and 0.8.
d. Converter input filter parameter design
In the converter proposed in this section, the input current is discontinuous, so in some applications where the harmonic factor of the input current is critical, an LC filter is needed to filter the input current, and an equivalent circuit diagram is shown in fig. 9 (d). The LC filter also has the effect of reducing electromagnetic interference and maintaining overall converter system stability.
When designing the input filter, it is desirable that the input impedance of the power supply system is as small as possible, i.e. the internal resistance of the power supply and the internal resistance formed by the LC filter are as small as possible, and the output impedance, i.e. the equivalent impedance of the converter is as large as possible, so that:
Z in ＜＜Z o (2-14)
in the design of the ac chopper, equations 2-14 can be replaced by empirical equations 2-15:
in the above formula, η is the efficiency of the converter, P O For output power, L is the input filter inductance, C is the input filter capacitance, R L Is the internal resistance, R, of the input filter inductance out As output impedance, R S Is the internal resistance of the power supply.
Example 3
The embodiment provides an alternating current converter for improving output gain, which is based on a right-angle magnetic coupling network alternating current converter, and a capacitor C and an inductor L are introduced into an input end 0 And forming the A-type quasi-Z source network alternating current converter.
Referring to fig. 5, the a-type quasi-Z source network ac converter includes:
AC power supply V in The first two-way switch S a A second bidirectional switch Sb and a transformerCoupling structure N, capacitor C and inductor L 0 Capacitor C 0 Load R, inductor L and capacitor C 1 Said AC power supply V in Through an inductor L and a first bidirectional switch S a A transformer coupling structure N, a capacitor C and the AC power supply V in Is connected to the second terminal of the first bi-directional switch S a Through a capacitor C 1 The second end of the transformer coupling structure N is connected with the second end of the transformer coupling structure N through a second bidirectional switch S b And the AC power supply V in The second end of the transformer coupling structure N is connected with the first end of the transformer coupling structure N through an inductor L 0 Capacitor C 0 And the AC power supply V in Is connected to the second terminal of the capacitor C 0 In parallel with the load R.
An A-type quasi-Z source network alternating current converter introduces an inductor L and a capacitor C on the basis of a right-angle type magnetic coupling network alternating current converter 1 As an energy storage element, the voltage gain of the alternating current converter is further improved, the current at the input end is smoothed through the inductor L, the electromagnetic compatibility characteristic of the alternating current converter can be improved, and the power grid pollution caused by input current harmonic waves is reduced.
Example 4
The embodiment provides an alternating current converter for improving output gain, which is based on a right-angle magnetic coupling network alternating current converter, and a capacitor C is introduced into an input end to form a B-type quasi Z-source network alternating current converter.
Referring to fig. 6, the b-type quasi-Z source network ac converter includes:
AC power supply V in The first two-way switch S a A second bidirectional switch S b A transformer coupling structure N, a capacitor C and an inductor L 0 Capacitor C 0 A load R and a capacitor C 1 Said AC power supply V in Through a first bidirectional switch S a A transformer coupling structure N, a capacitor C and the AC power supply V in Is connected to the second terminal of the first bidirectional switch S a Through a capacitor C 1 The third end of the transformer coupling structure N is connected withThrough a second bidirectional switch S b And the AC power supply V in The second end of the transformer coupling structure N is connected with the first end of the transformer coupling structure N through an inductor L 0 Capacitor C 0 And the AC power supply V in Is connected to the second terminal of the capacitor C 0 In parallel with the load R.
A Z-type quasi-Z source network AC converter introduces a capacitor C on the basis of a right-angle magnetic coupling network AC converter 1 The voltage gain of the ac converter is further improved as an energy storage element.
Example 5
The embodiment provides an ac converter for improving output gain, and an improved quasi-Z source network ac converter is formed by preposing a switch on the basis of the quasi-Z source network ac converter.
Referring to fig. 7, the improved quasi-Z source network ac converter includes:
AC power supply V in The first two-way switch S a A second bidirectional switch S b Transformer coupling structure N, capacitor C 0 Load R, inductor L and capacitor C 1 Said AC power supply V in Through an inductor L and a capacitor C 1 Transformer coupling structure N, second bidirectional switch S b And the AC power supply V in Is connected to the second terminal of the capacitor C 1 Through a first bidirectional switch S a The second end of the transformer coupling structure N is connected with the second end of the transformer coupling structure N through a capacitor C 0 And the AC power supply V in Is connected to the second terminal of the capacitor C 0 In parallel with the load R.
The quasi-Z source network AC converter in the embodiments 3 and 4 adopts the form of the traditional boost circuit at the output end, and the second bidirectional switch S at the output end b The stress of the transformer is larger and is approximately equal to the output high-gain voltage, so that the idea of switch preposition is adopted, the network topology structure of the alternating current converter is improved, the loss and the stress of a switch tube in the alternating current converter are reduced, and the efficiency of the alternating current converter is further improved.
Example 6
The present embodiment provides an ac converter for increasing output gain, which adds a voltage-multiplying capacitor C on the basis of an improved quasi-Z source network ac converter c And forming the enhanced alternating current converter.
Referring to fig. 8, an enhancement mode ac converter includes:
AC power supply V in The first two-way switch S a A second bidirectional switch S b A transformer coupling structure N and a capacitor C 0 Load R, inductor L, capacitor C1 and voltage-multiplying capacitor C c And a third bidirectional switch S c Said AC power supply V in A first end of the first bi-directional switch is connected with a first bi-directional switch S through a transformer coupling structure N a And the AC power supply V in Is connected to the second terminal of the transformer coupling structure N, the third terminal of the transformer coupling structure N is connected to the second terminal of the transformer coupling structure N via a second switch S b Voltage-multiplying capacitor C c And the AC power supply V in The second end of the transformer coupling structure N is connected with the first end of the transformer coupling structure through a capacitor C 1 A third two-way switch S c And the voltage-multiplying capacitor C c Is connected to the first terminal of the capacitor C 1 A second terminal of the filter is connected with an inductor L and a filter capacitor C 0 And the AC power supply V in Is connected with the second end of the filter capacitor C, the load R is connected with the filter capacitor C 0 And (4) connecting in parallel.
The enhancement type AC converter is an improved quasi-Z source AC converter of embodiment 5, and a voltage-multiplying capacitor C is introduced c The advantages of the front power module are absorbed by adopting a plurality of switch tubes, the purpose of improving the voltage is achieved by charging and discharging the capacitor in the TL network, and the efficiency of the power module is improved.
Referring to fig. 10, fig. 10 is a diagram for analyzing the switching behavior of the enhanced ac converter, fig. 10 (a) is the switching behavior in mode 1, and fig. 10 (b) is the switching process
The time switch is operated, and FIG. 10 (c) shows the switching process
The time-dependent switching operation is performed, and fig. 10 (d) shows the mode 2-dependent switching operation.
In State 1, S as in FIG. 10 (a) 2 、S 6 Opening, S 1 、S 6 Turning on and conducting current from the load to the power supply; s 3 Switching on for commutation. Thereafter, S 1 Is turned off and S 4 Not yet turned on, so there are two circuit states at this time. If it is not
Current flows through S 2 、S 6 As shown in FIG. 10 (b), if
Current flows through S 3 FIG. 10 (c). Mode 2 is shown in FIG. 10 (d), S 4 Switched on and current flows from the power supply to the load, S 3 Turning on the current that is transferred from the load to the power supply. In these switching modes, the current path is always continuous, which results in reduced voltage spikes during commutation. About V i Analysis with V < 0 i Similar to > 0, and therefore will not be described here.
In one switching period, the circuit system mainly has two switching modes, as shown in fig. 11, fig. 11 is an equivalent circuit diagram of two modes of the enhancement type Y-source high-gain AC-AC converter.
In the switching period DT, the circuit mode is as shown in fig. 11 (a).
In this case, the circuit satisfies the following equation:
when the switching period is (1-D) T, the circuit mode is as shown in fig. 11 (b).
In this case, the circuit satisfies the following equation:
the coupling type 5-1 and 5-2 can calculate the voltage transmission ratio, namely the voltage gain:
from the above equation, it can be seen that the voltage-doubling capacitor unit exists. The gain of this converter has been greatly increased. Theoretically analyze if N in the converter 2 Is close to N 1 The gain of the converter can be infinitely increased. In consideration of the efficiency of the circuit and the continuous and discontinuous condition of the inductive current, although the gain of the circuit system cannot reach infinity, compared with the prior converter, the converter has larger boosting capacity.
It should be noted that the first bidirectional switch S a And a second bidirectional switch S b And a third bidirectional switch S c Each MOS transistor consists of two MOS transistors which are connected in reverse; specifically, the MOS tube is an NMOS tube, the reverse connection means that a source electrode of the first NMOS tube is connected with a drain electrode of the second NMOS tube, and the NMOS tube receives PWM pulses sent by a chip to control the on-off of the PWM pulses, so that the voltage in positive and negative directions and the current in positive and negative directions are switched on and off.
By the method for designing an ac converter for improving output gain as set forth in embodiment 1, a series of ac converters can be designed, including: the right-angle magnetic coupling network alternating current converter of the embodiment 2, the quasi-Z source network alternating current converters of the embodiments 3 and 4, the improved quasi-Z source network alternating current converter of the embodiment 5 and the enhanced alternating current converter of the embodiment 6.
It should be noted that both the ac converter design method for increasing output gain and the subsequently proposed ac converters are based on the design idea of combining the ac chopper circuit and the transformer coupling structure, and have the advantages of simple structure, small size and high output gain. In addition, the alternating current converter can reduce the voltage stress of the switching tube, can smooth input current through the inductor L at the input end, reduces power grid pollution caused by input current harmonics, and does not need to be connected with a common mode inductor to optimize the electromagnetic compatibility RE102.
The above-mentioned embodiments are intended to illustrate the objects, technical solutions and advantages of the present invention in further detail, and it should be understood that the above-mentioned embodiments are merely exemplary embodiments of the present invention, and are not intended to limit the scope of the present invention, and any modifications, equivalent substitutions, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.
Claims (10)
1. A design method of an alternating current converter for improving output gain is characterized by comprising the following steps: the method comprises the following steps:
a right-angle transformer coupling structure is embedded in the alternating current chopper circuit to form a right-angle magnetic coupling network alternating current converter;
an inductor L and a capacitor C are introduced into the input end of the right-angle magnetic coupling network alternating current converter 1 Or introducing a capacitance C 1 Forming a quasi Z source network alternating current converter;
leading a switch in the quasi Z source network alternating current converter to form an improved quasi Z source network alternating current converter;
introducing a voltage-multiplying capacitor C into the improved quasi-Z source network alternating-current converter c And forming the enhanced alternating current converter.
2. An AC converter for increasing output gain, comprising: comprises that
AC power supply V in The first two-way switch S a A second bidirectional switch S b A transformer coupling structure N, a capacitor C and an inductor L 0 Capacitor C 0 And a load R, the AC power supply V in Through a first bidirectional switch S a A transformer coupling structure N, a capacitor C and the AC power supply V in Is connected to the second terminal of the transformer coupling structure N via a second bidirectional switch S b And the AC power supply V in Is connected to the second terminal of the transformer coupling structure N, the second terminal of the transformer coupling structure N is connected to the second terminal of the transformer coupling structure NInductor L 0 Capacitor C 0 And the AC power supply V in Is connected to the second terminal of the capacitor C 0 In parallel with the load R.
3. An AC converter for increasing output gain, comprising: comprises that
AC power supply V in The first two-way switch S a A second bidirectional switch Sb, a transformer coupling structure N, a capacitor C and an inductor L 0 Capacitor C 0 Load R, inductor L and capacitor C 1 Said AC power supply V in Through an inductor L and a first bidirectional switch S a A transformer coupling structure N, a capacitor C and the AC power supply V in Is connected to the second terminal of the first bidirectional switch S a Through a capacitor C 1 The second end of the transformer coupling structure N is connected with the second end of the transformer coupling structure N through a second bidirectional switch S b And the AC power supply V in The second end of the transformer coupling structure N is connected with the first end of the transformer coupling structure N through an inductor L 0 Capacitor C 0 And the AC power supply V in Is connected to the second terminal of the capacitor C 0 In parallel with the load R.
4. An AC converter for increasing output gain, comprising: comprises that
AC power supply V in A first bidirectional switch S a A second bidirectional switch S b A transformer coupling structure N, a capacitor C and an inductor L 0 Capacitor C 0 A load R and a capacitor C 1 Said AC power supply V in Through a first bidirectional switch S a A transformer coupling structure N, a capacitor C and the AC power supply V in Is connected to the second terminal of the first bidirectional switch S a Through a capacitor C 1 The second end of the transformer coupling structure N is connected with the third end of the transformer coupling structure N through a second bidirectional switch S b And the AC power supply V in Is connected to the second terminal of the transformer coupling structure N, the second terminal of the transformer coupling structure N is connected to the second terminal of the transformer coupling structure NInductor L 0 Capacitor C 0 And the AC power supply V in Is connected to the second terminal of the capacitor C 0 In parallel with the load R.
5. An AC converter for increasing output gain, comprising: comprises that
AC power supply V in The first two-way switch S a A second bidirectional switch S b Transformer coupling structure N, capacitor C 0 Load R, inductor L and capacitor C 1 Said AC power supply V in Through inductor L and capacitor C 1 Transformer coupling structure N, second bidirectional switch S b And the AC power supply V in Is connected to the second terminal of the capacitor C 1 Through a first bidirectional switch S a The second end of the transformer coupling structure N is connected with the second end of the transformer coupling structure N through a capacitor C 0 And the AC power supply V in To the second terminal of said capacitor C 0 In parallel with the load R.
6. An AC converter for increasing output gain, comprising: comprises that
AC power supply V in The first two-way switch S a A second bidirectional switch S b Transformer coupling structure N, capacitor C 0 Load R, inductor L, capacitor C1 and voltage-multiplying capacitor C c And a third bidirectional switch S c Said AC power supply V in A first end of the first bi-directional switch is connected with a first bi-directional switch S through a transformer coupling structure N a And the AC power supply V in Is connected to the second terminal of the transformer coupling structure N, the third terminal of the transformer coupling structure N is connected to the second terminal of the transformer coupling structure N via a second switch S b Voltage-multiplying capacitor C c And the AC power supply V in The second end of the transformer coupling structure N is connected with the first end of the transformer coupling structure through a capacitor C 1 A third two-way switch S c And the voltage-multiplying capacitor C c Is connected to the first terminal of the capacitor C 1 A second terminal of the filter passes through an inductor L and a filter capacitor C 0 And the AC power supply V in Is connected to the second end of the first connecting rod, theLoad R and filter capacitor C 0 And (4) connecting in parallel.
7. The ac converter as claimed in claim 6, wherein: the transformer coupling structure N is composed of two or three coupling inductors.
8. The ac converter as claimed in claim 7, wherein: the two coupling inductors form a T-shaped coupling structure, a Gamma-shaped coupling structure or an inverse Gamma-shaped coupling structure;
in the T-shaped coupling structure, a synonym end of a first coupling inductor is connected with a synonym end of a second inductor, the synonym end of the first coupling inductor is used as a first end of the transformer coupling structure, the synonym end of the first coupling inductor is used as a third end of the transformer coupling structure, and the synonym end of the second coupling inductor is used as a second end of the transformer coupling structure;
in the Gamma type coupling structure, a homonymous end of a first coupling inductor is connected with a homonymous end of a second inductor, the homonymous end of the first coupling inductor is used as a first end of a transformer coupling structure, a synonym end of the first coupling inductor is used as a second end of the transformer coupling structure, and the synonym end of the second coupling inductor is used as a third end of the transformer coupling structure;
in the inverse Gamma type coupling structure, the synonym end of a first coupling inductor is connected with the synonym end of a second inductor, the synonym end of the first coupling inductor is used as the first end of the transformer coupling structure, the synonym end of the first coupling inductor is used as the second end of the transformer coupling structure, and the synonym end of the second coupling inductor is used as the third end of the transformer coupling structure.
9. The ac converter of claim 7, wherein: the three coupling inductors form a Y-shaped coupling structure; in the Y-shaped coupling structure, a synonym end of a first coupling inductor, a synonym end of a second coupling inductor and a synonym end of a third coupling inductor are connected together, the synonym end of the first coupling inductor is used as a first end of the transformer coupling structure, the synonym end of the third coupling inductor is used as a second end of the transformer coupling structure, and the synonym end of the second coupling inductor is used as a third end of the transformer coupling structure.
10. The ac converter of claim 6, wherein: the first bidirectional switch S a And a second bidirectional switch S b Each composed of two MOS tubes connected in reverse.
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