Symmetrical unipolar input dc transformer

Abstract

The application provides a symmetrical unipolar input DC transformer, which comprises a DC power supply, a boost inductor, a switching module, a resonance module, a transformer module, a rectifier module and an output filter module, the output end of the DC power supply is connected with the input end of the switching module, the output end of the switching module is connected with the input end of the boost inductor, the output end of the boost inductor is connected with the input end of the resonance module, the output end of the resonance module is connected with the input end of the transformer module, the output end of the transformer module is connected with the input end of the rectifier module, the output end of the rectifier module is connected with the input end of the output filter module, the output end of the filter module is connected with a load, and the first switching module and the second switching module are symmetrically arranged at the two ends of the boost inductor. The proposed modular DC transformer has continuous input inductor current, reduces the design difficulty of an input filter, all semiconductor devices can realize soft switching, and the system efficiency and power density are improved.

Description

Technical Field

[0001] This invention belongs to the field of transformers, and particularly relates to a symmetrical unipolar input DC transformer. Background Technology

[0002] With the increasing penetration of renewable energy, medium-voltage DC technology is a solution to supplement and enhance existing AC power grids. Modular multilevel DC converters, due to their superior flexibility, scalability, and reliability, have become an optional topology for connecting different DC systems.

[0003] Existing technologies propose face-to-face topologies based on transformer coupling for high buck ratio conversion applications, but these suffer from low power density and high power loss. For low buck ratio conversion applications, existing technologies propose transformerless direct-connect structures, but these involve high current stress and expensive filters. Existing technologies also propose resonant modular multilevel DC transformers based on transformer coupling, which achieve soft switching of sub-modules through resonance between the sub-modules and the resonant inductor. However, the resonant frequency changes with the switching of operating modes and is directly related to the number of operating sub-modules, thus hindering system design. Furthermore, this topology requires expensive filter design. Existing technologies propose a modular multilevel DC transformer with a wide output range by adding auxiliary circuitry, but this increases system cost. Existing technologies also propose half-bridge modular DC transformers, but these cannot achieve soft switching of all switching transistors. Summary of the Invention

[0004] The purpose of this invention is to provide a symmetrical unipolar input DC transformer, which aims to solve the problems of low power density, resonant frequency being directly related to the number of sub-modules, expensive filters, and inability to achieve soft switching of all switching transistors in existing solutions.

[0005] This invention is implemented as follows: a symmetrical unipolar input DC transformer, including a DC power supply V. in Boost inductor L U1 The DC power supply V comprises a switching module, a resonant module, a transformer module, a rectifier module, and an output filter module. in The output terminal of the circuit is connected to the input terminal of the switching module, and the output terminal of the switching module is connected to the boost inductor L. U1 The input terminal is connected to the boost inductor L. U1The output terminal of the circuit is connected to the input terminal of the resonant module, the output terminal of the resonant module is connected to the input terminal of the transformer module, the output terminal of the transformer module is connected to the input terminal of the rectifier module, the output terminal of the rectifier module is connected to the input terminal of the output filter module, the output terminal of the filter module is connected to the load, and the load is connected to the circuit output terminal. The switching module includes a first switching module and a second switching module, which are symmetrically arranged on the boost inductor L. U1 The two ends.

[0006] A further technical solution of the present invention is: the resonant module includes a capacitor C. r and inductor L r The transformer module includes transformer T r and excitation inductance L m The rectifier module includes field-effect transistors SR1, SR2, SR3, and SR4; the output filter module includes capacitor C0; and the input terminal of the first switching module is connected to the DC power supply V. in The positive terminal is connected, and the output terminal of the first switching module is connected to the boost inductor L. U1 One end is connected to the boost inductor L U1 The other end is connected to the output terminal of the second switch module, and the input terminal of the second switch module is connected to the DC power supply V. in The negative terminal of the inductor L is connected. r One end of the inductor L is connected to the output terminal of the first switch module. r The other end is connected to the capacitor C r One end of the capacitor C is connected to the capacitor C. r The other end is connected to the transformer T r One end of the primary winding of the transformer T is connected. r The other end of the primary winding is connected to the output terminal of the second switching module, and the magnetizing inductor L m Located at the transformer T r Within the primary winding of the transformer T r One end of the secondary winding of the transformer is connected to the source of the field-effect transistor SR1. The drain of the field-effect transistor SR1 is connected to the drain of the field-effect transistor SR3. The source of the field-effect transistor SR3 is connected to the drain of the field-effect transistor SR4. The source of the field-effect transistor SR4 is connected to the source of the field-effect transistor SR2. The drain of the field-effect transistor SR2 is connected to the source of the field-effect transistor SR1. rThe other end of the secondary winding is connected to the drain of the field-effect transistor SR4. The drain of the field-effect transistor SR3 is connected to one end of the capacitor C0. The other end of the capacitor C0 is connected to the source of the field-effect transistor SR4. One end of the capacitor C0 is connected to the load R. Ld One end is connected, the load R Ld The other end is connected to the other end of the capacitor C0.

[0007] A further technical solution of the present invention is: the resonant module includes a capacitor C. Ur Capacitor C Lr Inductor L Ur and inductor L Lr The rectifier module includes field-effect transistors SR1, SR2, SR3, and SR4, and the output filter module includes capacitor C. 01 and capacitor C 02 The input terminal of the first switching module is connected to the DC power supply V. in The positive terminal is connected, and the output terminal of the first switching module is connected to the boost inductor L. U1 One end is connected to the boost inductor L U1 The other end is connected to the output terminal of the second switch module, and the input terminal of the second switch module is connected to the DC power supply V. in The negative terminal is connected, and the input terminal of the first switch module is connected to the capacitor C. 01 One end of the capacitor C is connected to the capacitor C. 01 The other end is connected to the drain of the field-effect transistor SR2, the source of the field-effect transistor SR2 is connected to the drain of the field-effect transistor SR1, and the source of the field-effect transistor SR2 is connected to the capacitor C. 01 One end is connected, and the source of the field-effect transistor SR2 is connected to the capacitor C. Ur One end of the capacitor C is connected to the capacitor C. Ur The other end is connected to the inductor L Ur One end is connected, the inductor L Ur The other end is connected to the boost inductor L U1 One end is connected, and the input terminal of the second switch module is connected to the capacitor C. 02 One end of the capacitor C is connected to the capacitor C. 02 The other end is connected to the source of the field-effect transistor SR3, the drain of the field-effect transistor SR3 is connected to the source of the field-effect transistor SR4, and the drain of the field-effect transistor SR4 is connected to the capacitor C. 02 One end is connected, and the source of the field-effect transistor SR4 is connected to the capacitor C. Lr One end of the capacitor C is connected to the capacitor C. Lr The other end is connected to the inductor L Lr One end is connected, the inductor LLr The other end is connected to the boost inductor L U1 The other end is connected, and the drain of the field-effect transistor SR2 and the source of the field-effect transistor SR3 are used as high-voltage output terminals.

[0008] A further technical solution of the present invention is: the resonant module includes a capacitor C. r Inductor L r Capacitor C Ur Capacitor C Lr Inductor L Ur and inductor L Lr The transformer module includes transformer T r and excitation inductance L m The rectifier module includes field-effect transistors SR1, SR2, SR3, and SR4, and the output filter module includes capacitor C0 and capacitor C1. 01 and capacitor C 02 The input terminal of the first switching module is connected to the DC power supply V. in The positive terminal is connected, and the output terminal of the first switching module is connected to the boost inductor L. U1 One end is connected to the boost inductor L U1 The other end is connected to the output terminal of the second switch module, and the input terminal of the second switch module is connected to the DC power supply V. in The negative terminal is connected, and the input terminal of the first switch module is connected to the capacitor C. 01 One end of the capacitor C is connected to the capacitor C. 01 The other end is connected to the drain of the field-effect transistor SR2, the source of the field-effect transistor SR2 is connected to the drain of the field-effect transistor SR1, and the source of the field-effect transistor SR2 is connected to the capacitor C. 01 One end is connected, and the source of the field-effect transistor SR2 is connected to the capacitor C. Ur One end of the capacitor C is connected to the capacitor C. Ur The other end is connected to the inductor L Ur One end is connected, the inductor L Ur The other end is connected to the boost inductor L U1 One end is connected, and the input terminal of the second switch module is connected to the capacitor C. 02 One end of the capacitor C is connected to the capacitor C. 02 The other end is connected to the source of the field-effect transistor SR3, the drain of the field-effect transistor SR3 is connected to the source of the field-effect transistor SR4, and the drain of the field-effect transistor SR4 is connected to the capacitor C. 02 One end is connected, and the source of the field-effect transistor SR4 is connected to the capacitor C. Lr One end of the capacitor C is connected to the capacitor C. Lr The other end is connected to the inductor LLr One end is connected, the inductor L Lr The other end is connected to the boost inductor L U1 The other end is connected to the inductor L Ur The other end is connected to the inductor L r One end is connected, the inductor L r The other end is connected to the capacitor C r One end of the capacitor C is connected to the capacitor C. r The other end is connected to the transformer T r One end of the primary winding of the transformer T is connected. r The other end of the primary winding is connected to the inductor L Lr The other end is connected to the excitation inductor L m Located at the transformer T r Within the primary winding of the transformer T r One end of the secondary winding of the transformer is connected to the source of the field-effect transistor SR1. The drain of the field-effect transistor SR1 is connected to the drain of the field-effect transistor SR3. The source of the field-effect transistor SR3 is connected to the drain of the field-effect transistor SR4. The source of the field-effect transistor SR4 is connected to the source of the field-effect transistor SR2. The drain of the field-effect transistor SR2 is connected to the source of the field-effect transistor SR1. r The other end of the secondary winding is connected to the drain of the field-effect transistor SR4. The drain of the field-effect transistor SR3 is connected to one end of the capacitor C0. The other end of the capacitor C0 is connected to the source of the field-effect transistor SR4. One end of the capacitor C0 is connected to the load R. Ld One end is connected, the load R Ld The other end is connected to the other end of the capacitor C0, and the drain of the field-effect transistor SR2 and the source of the field-effect transistor SR3 are used as high-voltage output terminals.

[0009] A further technical solution of the present invention is as follows: the switching module is composed of several switching circuits SM connected in series. The switching circuit SM adopts a first half-bridge switch and / or a second half-bridge switch, and / or a full-bridge switch. The first half-bridge switch includes a field-effect transistor Q1, a field-effect transistor Q2, and a capacitor C1. The drain of the field-effect transistor Q1 is connected to one end of the capacitor C1, and the other end of the capacitor C1 is connected to the source of the field-effect transistor Q2. The drain of the field-effect transistor Q2 is connected to the source of the field-effect transistor Q1. The source and drain of the field-effect transistor Q2 are outputs. The second half-bridge switch includes a field-effect transistor Q1. 11 , field-effect transistor Q 21 and capacitor C2, the field-effect transistor Q 11 The drain of the capacitor is connected to one end of the capacitor C2, and the other end of the capacitor C2 is connected to the field-effect transistor Q. 21The source connection of the field-effect transistor Q 21 The drain of the field-effect transistor Q 11 The source connection of the field-effect transistor Q 11 The source and drain outputs; the full-bridge switch includes a field-effect transistor Q. 12 , field-effect transistor Q 22 Field-effect transistors Q3 and Q4, and capacitor C3, wherein the field-effect transistor Q... 12 The drain of the transistor is connected to the drain of the field-effect transistor Q3. 12 The source of the field-effect transistor Q 22 The drain connection of the field-effect transistor Q 22 The source of capacitor C3 is connected to the source of transistor Q4, the source of transistor Q3 is connected to the drain of transistor Q4, and one end of capacitor C3 is connected to the drain of transistor Q4. 12 The drain of capacitor C3 is connected to the drain of transistor Q. The other end of capacitor C3 is connected to the field-effect transistor Q. 22 The source connection of the field-effect transistor Q 12 The source of the transistor is the same as the source output of the field-effect transistor Q3.

[0010] The beneficial effects of this invention are: the proposed modular DC transformer has a continuous input inductor current, which reduces the design difficulty of the input filter; all semiconductor devices can achieve soft switching, which improves system efficiency and power density; in addition, when the converter is designed to operate in resonant mode, the resonant frequency is independent of the number of operating sub-modules, which facilitates system design. Attached Figure Description

[0011] Figure 1 This is the first implementation circuit of the symmetrical unipolar input DC transformer provided in the embodiments of the present invention; Figure 2 This is a second implementation circuit of the symmetrical unipolar input DC transformer provided in the embodiments of the present invention; Figure 3 This is an embodiment of the circuit provided by the present invention, which has a non-isolated output and one isolated output. Figure 4 The circuit diagram of the first half-bridge switch is shown; Figure 5 The circuit diagram of the second half-bridge switch is shown; Figure 6 The circuit diagram of the full-bridge switch is shown; Figure 7 The implementation circuits of the primary and secondary resonant cavities of the transformer are shown; Figure 8 The implementation circuit of the transformer secondary side and the rectifier is shown; Figure 9The implementation circuit of the modular DC transformer using an input series and output parallel architecture is shown. Detailed Implementation

[0012] Figure reference numerals: 100 - Modular DC transformer, 101 - DC power supply V in 102-Boost Inductor L U1 103-Switch module, 104-Resonant module, 105-Transformer module, 106-Rectifier module, 107-Output filter module, 108-Load.

[0013] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0014] The DC transformer solution provided by this invention modularizes each component, allowing for various topological changes within a single modular circuit to suit different circuit conditions and reduce the need for input filter design. Furthermore, the proposed DC transformer enables soft switching of all transistors, improving system efficiency and power density. When the converter operates in resonant mode, the resonant frequency is independent of the number of operating sub-modules, facilitating system design. This invention provides a symmetrical unipolar input DC transformer, including a DC power supply V. in 101. Boost Inductor L U1 102, 103, 104, 105, 106, 107, and the DC power supply V in The output terminal of 101 is connected to the input terminal of the switching module 103, and the output terminal of the switching module 103 is connected to the boost inductor L. U1 The input terminal of 102 is connected to the boost inductor L. U1 The output terminal of 102 is connected to the input terminal of the resonant module 104. The output terminal of the resonant module 104 is connected to the input terminal of the transformer module 105. The output terminal of the transformer module 105 is connected to the input terminal of the rectifier module 106. The output terminal of the rectifier module 106 is connected to the input terminal of the output filter module 107. The output terminal of the filter module is connected to the load 108. The load 108 is connected to the circuit output terminal. The switching module 103 includes a first switching module and a second switching module, which are symmetrically arranged on the boost inductor L. U1 The two ends of 102. For example... Figures 1-3 As shown, the circuit provided by this invention is a symmetrically arranged circuit, utilizing the boost inductor L. U1 102 is designed as a symmetrical neutral point.

[0015] Figure 1 This demonstrates the basic circuit configuration of the present invention, which is a first implementation circuit of a symmetrical unipolar input DC transformer. The resonant module 104 includes a capacitor C. r and inductor L r The transformer module 105 includes a transformer T r and excitation inductance L m The rectifier module 106 includes field-effect transistors SR1, SR2, SR3, and SR4. The output filter module 107 includes capacitor C0. The input terminal of the first switching module is connected to the DC power supply V. in The positive terminal of 101 is connected, and the output terminal of the first switching module is connected to the boost inductor L. U1 One end of 102 is connected to the boost inductor L. U1 The other end of 102 is connected to the output terminal of the second switching module, and the input terminal of the second switching module is connected to the DC power supply V. in The negative terminal of 101 is connected, and the inductor L r One end of the inductor L is connected to the output terminal of the first switch module. r The other end is connected to the capacitor C r One end of the capacitor C is connected to the capacitor C. r The other end is connected to the transformer T r One end of the primary winding of the transformer T is connected. r The other end of the primary winding is connected to the output terminal of the second switching module, and the magnetizing inductor L m Located at the transformer T r Within the primary winding of the transformer T r One end of the secondary winding of the transformer is connected to the source of the field-effect transistor SR1. The drain of the field-effect transistor SR1 is connected to the drain of the field-effect transistor SR3. The source of the field-effect transistor SR3 is connected to the drain of the field-effect transistor SR4. The source of the field-effect transistor SR4 is connected to the source of the field-effect transistor SR2. The drain of the field-effect transistor SR2 is connected to the source of the field-effect transistor SR1. r The other end of the secondary winding is connected to the drain of the field-effect transistor SR4. The drain of the field-effect transistor SR3 is connected to one end of the capacitor C0. The other end of the capacitor C0 is connected to the source of the field-effect transistor SR4. One end of the capacitor C0 is connected to the load R. Ld One end is connected, the load R Ld The other end is connected to the other end of the capacitor C0. This embodiment can be used when the input voltage has no neutral point, by inputting the boost inductor L... U1 The magnetizing inductance L of 102 and the transformer mTogether, they enable soft switching of switching devices in the switching network.

[0016] like Figure 2 As shown, the resonant module 104 includes a capacitor C. Ur Capacitor C Lr Inductor L Ur and inductor L Lr The rectifier module 106 includes field-effect transistors SR1, SR2, SR3, and SR4, and the output filter module 107 includes capacitor C. 01 and capacitor C 02 The input terminal of the first switching module is connected to the DC power supply V. in The positive terminal of 101 is connected, and the output terminal of the first switching module is connected to the boost inductor L. U1 One end of 102 is connected to the boost inductor L. U1 The other end of 102 is connected to the output terminal of the second switch module, and the input terminal of the second switch module is connected to the DC power supply V. in The negative terminal of 101 is connected, and the input terminal of the first switch module is connected to the capacitor C. 01 One end of the capacitor C is connected to the capacitor C. 01 The other end is connected to the drain of the field-effect transistor SR2, the source of the field-effect transistor SR2 is connected to the drain of the field-effect transistor SR1, and the source of the field-effect transistor SR2 is connected to the capacitor C. 01 One end is connected, and the source of the field-effect transistor SR2 is connected to the capacitor C. Ur One end of the capacitor C is connected to the capacitor C. Ur The other end is connected to the inductor L Ur One end is connected, the inductor L Ur The other end is connected to the boost inductor L U1 One end of 102 is connected, and the input terminal of the second switch module is connected to the capacitor C. 02 One end of the capacitor C is connected to the capacitor C. 02 The other end is connected to the source of the field-effect transistor SR3, the drain of the field-effect transistor SR3 is connected to the source of the field-effect transistor SR4, and the drain of the field-effect transistor SR4 is connected to the capacitor C. 02 One end is connected, and the source of the field-effect transistor SR4 is connected to the capacitor C. Lr One end of the capacitor C is connected to the capacitor C. Lr The other end is connected to the inductor L Lr One end is connected, the inductor L Lr The other end is connected to the boost inductor L U1The other end of 102 is connected, with the drain of the field-effect transistor SR2 and the source of the field-effect transistor SR3 serving as the high-voltage output. This embodiment is a second implementation circuit of a symmetrical unipolar input DC transformer, which can connect to two medium- and high-voltage DC buses.

[0017] Figure 3 An implementation circuit with a non-isolated output and one isolated output is shown. The resonant module 104 includes a capacitor C. r Inductor L r Capacitor C Ur Capacitor C Lr Inductor L Ur and inductor L Lr The transformer module 105 includes a transformer T r and excitation inductance L m The rectifier module 106 includes field-effect transistors SR1, SR2, SR3, and SR4; the output filter module 107 includes capacitors C0 and C1. 01 and capacitor C 02 The input terminal of the first switching module is connected to the DC power supply V. in The positive terminal of 101 is connected, and the output terminal of the first switching module is connected to the boost inductor L. U1 One end of 102 is connected to the boost inductor L. U1 The other end of 102 is connected to the output terminal of the second switch module, and the input terminal of the second switch module is connected to the DC power supply V. in The negative terminal of 101 is connected, and the input terminal of the first switch module is connected to the capacitor C. 01 One end of the capacitor C is connected to the capacitor C. 01 The other end is connected to the drain of the field-effect transistor SR2, the source of the field-effect transistor SR2 is connected to the drain of the field-effect transistor SR1, and the source of the field-effect transistor SR2 is connected to the capacitor C. 01 One end is connected, and the source of the field-effect transistor SR2 is connected to the capacitor C. Ur One end of the capacitor C is connected to the capacitor C. Ur The other end is connected to the inductor L Ur One end is connected, the inductor L Ur The other end is connected to the boost inductor L U1 One end of 102 is connected, and the input terminal of the second switch module is connected to the capacitor C. 02 One end of the capacitor C is connected to the capacitor C. 02 The other end is connected to the source of the field-effect transistor SR3, the drain of the field-effect transistor SR3 is connected to the source of the field-effect transistor SR4, and the drain of the field-effect transistor SR4 is connected to the capacitor C. 02One end is connected, and the source of the field-effect transistor SR4 is connected to the capacitor C. Lr One end of the capacitor C is connected to the capacitor C. Lr The other end is connected to the inductor L Lr One end is connected, the inductor L Lr The other end is connected to the boost inductor L U1 The other end of 102 is connected to the inductor L. Ur The other end is connected to the inductor L r One end is connected, the inductor L r The other end is connected to the capacitor C r One end of the capacitor C is connected to the capacitor C. r The other end is connected to the transformer T r One end of the primary winding of the transformer T is connected. r The other end of the primary winding is connected to the inductor L Lr The other end is connected to the excitation inductor L m Located at the transformer T r Within the primary winding of the transformer T r One end of the secondary winding of the transformer is connected to the source of the field-effect transistor SR1. The drain of the field-effect transistor SR1 is connected to the drain of the field-effect transistor SR3. The source of the field-effect transistor SR3 is connected to the drain of the field-effect transistor SR4. The source of the field-effect transistor SR4 is connected to the source of the field-effect transistor SR2. The drain of the field-effect transistor SR2 is connected to the source of the field-effect transistor SR1. r The other end of the secondary winding is connected to the drain of the field-effect transistor SR4. The drain of the field-effect transistor SR3 is connected to one end of the capacitor C0. The other end of the capacitor C0 is connected to the source of the field-effect transistor SR4. One end of the capacitor C0 is connected to the load R. Ld One end is connected, the load R Ld The other end is connected to the other end of the capacitor C0, and the drain of the field-effect transistor SR2 and the source of the field-effect transistor SR3 serve as high-voltage output terminals. This embodiment can reduce the DC voltage bias of the capacitor in the resonant module 104 to zero, thus facilitating capacitor design. Furthermore, when the resonant module 104 is no longer operating in resonant mode, this capacitor can be omitted, further reducing costs.

[0018] The switching module is composed of several switching circuits SM connected in series. In this invention, two switching modules 103 are provided, namely the first switching module and the second switching module. Both the first and second switching modules are composed of switching circuits SM connected in series. The switching circuits SM adopt a first half-bridge switch and / or a second half-bridge switch, and / or a full-bridge switch. The first half-bridge switch includes a field-effect transistor Q1, a field-effect transistor Q2, and a capacitor C1. The drain of the field-effect transistor Q1 is connected to one end of the capacitor C1, and the other end of the capacitor C1 is connected to the source of the field-effect transistor Q2. The drain of the field-effect transistor Q2 is connected to the source of the field-effect transistor Q1. The source and drain of the field-effect transistor Q2 are outputs. The second half-bridge switch includes a field-effect transistor Q1, a second half-bridge switch Q2, and a third half-bridge switch Q2. 11 , field-effect transistor Q 21 and capacitor C2, the field-effect transistor Q 11 The drain of the capacitor is connected to one end of the capacitor C2, and the other end of the capacitor C2 is connected to the field-effect transistor Q. 21 The source connection of the field-effect transistor Q 21 The drain of the field-effect transistor Q 11 The source connection of the field-effect transistor Q 11 The source and drain outputs; the full-bridge switch includes a field-effect transistor Q. 12 , field-effect transistor Q 22 Field-effect transistors Q3 and Q4, and capacitor C3, wherein the field-effect transistor Q... 12 The drain of the transistor is connected to the drain of the field-effect transistor Q3. 12 The source of the field-effect transistor Q 22 The drain connection of the field-effect transistor Q 22 The source of capacitor C3 is connected to the source of transistor Q4, the source of transistor Q3 is connected to the drain of transistor Q4, and one end of capacitor C3 is connected to the drain of transistor Q4. 12 The drain of capacitor C3 is connected to the drain of transistor Q. The other end of capacitor C3 is connected to the field-effect transistor Q. 22 The source connection of the field-effect transistor Q 12 The source of the transistor is the same as the source output of the field-effect transistor Q3. For example... Figure 4-6 As shown, the switching module 103 is composed of several switching circuits SM connected in series. The switching module can be a half-bridge sub-module and / or a full-bridge sub-module. The switching network module can be formed by other types of controllable devices, such as metal-oxide-semiconductor field-effect transistors (MOSFETs), bipolar junction transistors (BJTs), superjunction transistors (SJTs), insulated-gate bipolar transistors (IGBTs), gallium nitride (GaN) devices, etc.

[0019] Figure 7 and Figure 8 In this context, the resonant module 104 can be implemented in various ways. It can operate in a resonant state, such as an inductor-inductor-capacitor (LLC) resonant circuit and / or similar circuits. Alternatively, it can operate in a non-resonant state, using a structure such as a DC blocking capacitor-inductor or an inductor without a DC blocking capacitor. When the modular DC transformer 100 requires bidirectional operation, the resonant module 104 can be added to the primary and secondary sides of the transformer module 105, respectively. Figure 7 As shown, this enables bidirectional step-up and step-down voltage capabilities. Series and parallel resonant inductors can be implemented as external inductors. For example, a series resonant inductor can be implemented as the leakage inductance of the transformer module 105.

[0020] In this embodiment, the transformer module 105 can be a transformer consisting of two windings, or it can be as follows: Figure 8 The transformer shown is composed of three windings. Furthermore, the transformer module 105 can be replaced and / or omitted using inductors, thereby forming a non-isolated modular DC transformer 100. It should be noted that the transformers described above and throughout the specification are merely examples and should not unduly limit the scope of the claims. The transformer module 105 may also further include various bias windings and gate drive auxiliary windings.

[0021] In this embodiment, the rectifier module 106 converts the alternating polarity waveform received from the output terminal of the transformer module 105 into a unipolar waveform. The rectifier module 106 can be a rectifier structure composed of diodes, or it can employ a full-wave rectifier structure, such as... Figure 8 As shown in the diagram. Furthermore, the rectifier module 106 can be formed from other types of controllable devices, such as metal-oxide-semiconductor field-effect transistors (MOSFETs), bipolar junction transistors (BJTs), superjunction transistors (SJTs), insulated-gate bipolar transistors (IGBTs), gallium nitride (GaN) devices, etc. In this embodiment, when the rectifier module 106 uses fully controllable devices, the circuit can achieve bidirectional energy flow.

[0022] In an embodiment, the output filter module 107 may be composed of a capacitor or an LC filter consisting of an inductor-capacitor.

[0023] The DC power supply V in 101 can be a power supply that converts mains voltage to DC voltage. Alternatively, the DC power supply V in 101 can be a solar panel array. Additionally, the DC power supply V... in101 can be an energy storage device such as a rechargeable battery or a fuel cell. The load 108 represents the power consumed by a circuit coupled to the modular DC transformer 100. Alternatively, the load 108 can refer to a downstream converter coupled to the output of the modular DC transformer 100.

[0024] like Figure 9 As shown, the modular DC transformer 100 can be implemented using an input series and output parallel architecture, suitable for high-voltage, high-current output applications. Each submodule can be selected from... Figures 1-3 The modular DC transformer 100 of any embodiment can be combined to form a circuit for processing high-power power supplies.

[0025] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A symmetrical unipolar input DC transformer, characterized in that, Including DC power supply V in Boost inductor L U1 The DC power supply V comprises a switching module, a resonant module, a transformer module, a rectifier module, and an output filter module. in The output terminal is connected to one end of the switching module, and the other end of the switching module is connected to the boost inductor L. U1 One end is connected to the boost inductor L U1 The other end is connected to one end of the resonant module, the other end of the resonant module is connected to the primary side of the transformer module, the secondary side of the transformer module is connected to the input terminal of the rectifier module, the output terminal of the rectifier module is connected to the input terminal of the output filter module, the output terminal of the filter module is connected to the load, and the load is connected to the circuit output terminal. The switching module includes a first switching module and a second switching module, which are symmetrically arranged on the boost inductor L. U1 The two ends.

2. A symmetrical unipolar input DC transformer according to claim 1, characterized in that, The resonant module includes capacitor C. r and inductor L r The transformer module includes transformer T r and excitation inductance L m The rectifier module includes field-effect transistors SR1, SR2, SR3, and SR4; the output filter module includes capacitor C0; and the input terminal of the first switching module is connected to the DC power supply V. in The positive terminal is connected, and the output terminal of the first switching module is connected to the boost inductor L. U1 One end is connected to the boost inductor L U1 The other end is connected to the output terminal of the second switch module, and the input terminal of the second switch module is connected to the DC power supply V. in The negative terminal of the inductor L is connected. r One end of the inductor L is connected to the output terminal of the first switch module. r The other end is connected to the capacitor C r One end of the capacitor C is connected to the capacitor C. r The other end is connected to the transformer T r One end of the primary winding of the transformer T is connected. r The other end of the primary winding is connected to the output terminal of the second switching module, and the magnetizing inductor L m Assuming the transformer T r Within the primary winding of the transformer T r One end of the secondary winding of the transformer is connected to the source of the field-effect transistor SR1. The drain of the field-effect transistor SR1 is connected to the drain of the field-effect transistor SR3. The source of the field-effect transistor SR3 is connected to the drain of the field-effect transistor SR4. The source of the field-effect transistor SR4 is connected to the source of the field-effect transistor SR2. The drain of the field-effect transistor SR2 is connected to the source of the field-effect transistor SR1. r The other end of the secondary winding is connected to the drain of the field-effect transistor SR4. The drain of the field-effect transistor SR3 is connected to one end of the capacitor C0. The other end of the capacitor C0 is connected to the source of the field-effect transistor SR4. One end of the capacitor C0 is connected to the load R. Ld One end is connected, the load R Ld The other end is connected to the other end of the capacitor C0.

3. A symmetrical unipolar input DC transformer according to claim 1, characterized in that, The resonant module includes capacitor C. Ur Capacitor C Lr Inductor L Ur and inductor L Lr The rectifier module includes field-effect transistors SR1, SR2, SR3, and SR4, and the output filter module includes capacitor C. 01 and capacitor C 02 The input terminal of the first switching module is connected to the DC power supply V. in The positive terminal is connected, and the output terminal of the first switching module is connected to the boost inductor L. U1 One end is connected to the boost inductor L U1 The other end is connected to the output terminal of the second switch module, and the input terminal of the second switch module is connected to the DC power supply V. in The negative terminal is connected, and the input terminal of the first switch module is connected to the capacitor C. 01 One end of the capacitor C is connected to the capacitor C. 01 The other end is connected to the drain of the field-effect transistor SR2, the source of the field-effect transistor SR2 is connected to the drain of the field-effect transistor SR1, and the source of the field-effect transistor SR1 is connected to the capacitor C. 01 One end is connected, and the source of the field-effect transistor SR2 is connected to the capacitor C. Ur One end of the capacitor C is connected to the capacitor C. Ur The other end is connected to the inductor L Ur One end is connected, the inductor L Ur The other end is connected to the boost inductor L U1 One end is connected, and the input terminal of the second switch module is connected to the capacitor C. 02 One end of the capacitor C is connected to the capacitor C. 02 The other end is connected to the source of the field-effect transistor SR3, the drain of the field-effect transistor SR3 is connected to the source of the field-effect transistor SR4, and the drain of the field-effect transistor SR4 is connected to the capacitor C. 02 One end is connected, and the source of the field-effect transistor SR4 is connected to the capacitor C. Lr One end of the capacitor C is connected to the capacitor C. Lr The other end is connected to the inductor L Lr One end is connected, the inductor L Lr The other end is connected to the boost inductor L U1 The other end is connected, and the drain of the field-effect transistor SR2 and the source of the field-effect transistor SR3 are used as high-voltage output terminals.

4. A symmetrical unipolar input DC transformer according to claim 1, characterized in that, The resonant module includes capacitor C. r Inductor L r Capacitor C Ur Capacitor C Lr Inductor L Ur and inductor L Lr The transformer module includes transformer T r and excitation inductance L m The rectifier module includes field-effect transistors SR1, SR2, SR3, and SR4, and the output filter module includes capacitor C0 and capacitor C1. 01 and capacitor C 02 The input terminal of the first switching module is connected to the DC power supply V. in The positive terminal is connected, and the output terminal of the first switching module is connected to the boost inductor L. U1 One end is connected to the boost inductor L U1 The other end is connected to the output terminal of the second switch module, and the input terminal of the second switch module is connected to the DC power supply V. in The negative terminal is connected, and the input terminal of the first switch module is connected to the capacitor C. 01 One end of the capacitor C is connected to the capacitor C. 01 The other end is connected to the drain of the field-effect transistor SR2, the source of the field-effect transistor SR2 is connected to the drain of the field-effect transistor SR1, and the source of the field-effect transistor SR1 is connected to the capacitor C. 01 One end is connected, and the source of the field-effect transistor SR2 is connected to the capacitor C. Ur One end of the capacitor C is connected to the capacitor C. Ur The other end is connected to the inductor L Ur One end is connected, the inductor L Ur The other end is connected to the boost inductor L U1 One end is connected, and the input terminal of the second switch module is connected to the capacitor C. 02 One end of the capacitor C is connected to the capacitor C. 02 The other end is connected to the source of the field-effect transistor SR3, the drain of the field-effect transistor SR3 is connected to the source of the field-effect transistor SR4, and the drain of the field-effect transistor SR4 is connected to the capacitor C. 02 One end is connected, and the source of the field-effect transistor SR4 is connected to the capacitor C. Lr One end of the capacitor C is connected to the capacitor C. Lr The other end is connected to the inductor L Lr One end is connected, the inductor L Lr The other end is connected to the boost inductor L U1 The other end is connected to the inductor L Ur The other end is connected to the inductor L r One end is connected, the inductor L r The other end is connected to the capacitor C r One end of the capacitor C is connected to the capacitor C. r The other end is connected to the transformer T r One end of the primary winding of the transformer T is connected. r The other end of the primary winding is connected to the inductor L Lr The other end is connected to the excitation inductor L m Assuming the transformer T r Within the primary winding of the transformer T r One end of the secondary winding of the transformer is connected to the source of the field-effect transistor SR1. The drain of the field-effect transistor SR1 is connected to the drain of the field-effect transistor SR3. The source of the field-effect transistor SR3 is connected to the drain of the field-effect transistor SR4. The source of the field-effect transistor SR4 is connected to the source of the field-effect transistor SR2. The drain of the field-effect transistor SR2 is connected to the source of the field-effect transistor SR1. r The other end of the secondary winding is connected to the drain of the field-effect transistor SR4. The drain of the field-effect transistor SR3 is connected to one end of the capacitor C0. The other end of the capacitor C0 is connected to the source of the field-effect transistor SR4. One end of the capacitor C0 is connected to the load R. Ld One end is connected, the load R Ld The other end is connected to the other end of the capacitor C0, and the drain of the field-effect transistor SR3 and the source of the field-effect transistor SR2 are used as high-voltage output terminals.

5. A symmetrical unipolar input DC transformer according to any one of claims 1-4, characterized in that, The switching module consists of several switching circuits SM connected in series. Each switching circuit SM employs a first half-bridge switch and / or a second half-bridge switch, and / or a full-bridge switch. The first half-bridge switch includes a field-effect transistor (FET) Q1, a field-effect transistor (FET) Q2, and a capacitor C1. The drain of FET Q1 is connected to one end of capacitor C1, and the other end of capacitor C1 is connected to the source of FET Q2. The drain of FET Q2 is connected to the source of FET Q1. The source and drain of FET Q2 are outputs. The second half-bridge switch includes a field-effect transistor Q1... 11 , field-effect transistor Q 21 and capacitor C2, the field-effect transistor Q 11 The drain of the capacitor is connected to one end of the capacitor C2, and the other end of the capacitor C2 is connected to the field-effect transistor Q. 21 The source connection of the field-effect transistor Q 21 The drain of the field-effect transistor Q 11 The source connection of the field-effect transistor Q 11 The source and drain outputs; the full-bridge switch includes a field-effect transistor Q. 12 MOSFET Q 22 Field-effect transistors Q3 and Q4, and capacitor C3, wherein the field-effect transistor Q... 12 The drain of the transistor is connected to the drain of the field-effect transistor Q3. 12 The source of the field-effect transistor Q 22 The drain connection of the field-effect transistor Q 22 The source of capacitor C3 is connected to the source of transistor Q4, the source of transistor Q3 is connected to the drain of transistor Q4, and one end of capacitor C3 is connected to the drain of transistor Q4. 12 The drain of capacitor C3 is connected to the drain of transistor Q. The other end of capacitor C3 is connected to the field-effect transistor Q. 22 The source connection of the field-effect transistor Q 12 The source of the transistor is the same as the source output of the field-effect transistor Q3.

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