A novel multi-resonant three-port converter for simultaneous transmission of fundamental and third harmonic energy and a control method thereof

Abstract

The application discloses a novel multi-resonance three-port converter for simultaneously transmitting fundamental wave and third harmonic wave energy and a control method, and belongs to the technical field of power electronic converters. The novel multi-resonance three-port converter comprises three independent port circuits, each of which is connected with a corresponding bidirectional direct-current voltage source, and the specific connection structure is as follows: the three port circuits are a port 1 circuit, a port 2 circuit and a port 3 circuit. The application realizes the synchronous transmission of the fundamental wave and the third harmonic wave energy, does not need to separately design independent transmission channels for different frequency powers, and greatly simplifies the overall topology structure of the system; meanwhile, the power decoupling between the ports is realized by relying on the precise parameter configuration of the resonant cavity, the power cross-coupling interference between the fundamental wave and the third harmonic wave is effectively inhibited, and the stability and reliability of the multi-frequency power transmission are improved.

Description

Technical Field

[0001] This invention relates to the field of power electronic converter technology, specifically to a novel multi-resonant three-port converter and control method for simultaneous transmission of fundamental and third harmonic energy. Background Technology

[0002] To address the environmental and resource pressures caused by the overuse of fossil fuels, new energy generation and storage technologies, represented by photovoltaics, wind power, and energy storage batteries, have been rapidly promoted and applied in China. DC microgrids, due to their outstanding advantages in efficiently absorbing new energy sources, flexibly controlling energy storage systems, and stably supporting data center power supply, have received widespread attention from academia and industry and are gradually being implemented. Power electronic converters, as the core equipment of DC microgrids, are responsible for realizing the conversion and efficient transmission of power between different units. While traditional common DC bus architectures offer good system scalability, they rely on multiple independent two-port converters, leading to an increase in the number of components, higher system costs, and increased control complexity. To address these shortcomings of traditional structures, three-port converters have been proposed and have become a research hotspot.

[0003] However, traditional three-port converters based on the fundamental power transfer mechanism still have shortcomings such as low DC voltage utilization and high current stress, which in turn lead to problems such as limited system transmission power and high conduction loss. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to address the shortcomings of the above-mentioned background technology by proposing a novel multi-resonant three-port converter and control method for simultaneous transmission of fundamental and third harmonic energy.

[0005] To achieve the above-mentioned objectives, the present invention employs the following technical solution: A novel multi-resonant three-port converter that simultaneously transmits fundamental and third harmonic energy includes three independent port circuits, each connected to a corresponding bidirectional DC voltage source. The specific connection structure is as follows: the three port circuits are port 1, port 2, and port 3; port 1 includes a bidirectional DC voltage source. U 1. Switching transistor S 1. Switching transistor S 2. Switching transistor S 3. Switching transistor S 4. Resonant capacitor Cr 11 Resonant inductor Lr 11 Resonant inductor Lr 12 Transformer windings n 1; The bidirectional DC voltage source U 1's positive terminal and the switching transistor S1's drain and switching transistor S The drains of transistor 3 are connected, and the switching transistor is... S The source of 1 is connected to the switching transistor. S 2's drain and resonant capacitor Cr 11 Cathode, resonant inductor Lr 12 The cathode is connected, and the resonant capacitor is connected. Cr 11 The positive terminal and the resonant inductor Lr 11 The cathodes are connected, and the resonant inductor is connected. Lr 11 The positive terminals are respectively connected to the resonant inductor Lr 12 Positive terminal, transformer winding n The positive terminal of 1 is connected to the transformer winding. n Cathode and resonant capacitor of 1 Cr 12 The positive terminal is connected, and the resonant capacitor is resonant. Cr 12 The cathodes are respectively connected to the switching transistor S 3's source and switch S The drains of 4 are connected, and the switching transistor is... S The source of 4 is connected to the switching transistor. S 2's source, bidirectional DC voltage source U The cathode of port 1 is connected; the circuit of port 2 includes a bidirectional DC voltage source. U 2. Switching transistor S 5. Switching transistor S 6. Switching transistor S 7. Switching transistor S 8. Resonant capacitor Cr 21 Resonant inductor Lr 22 Resonant inductor Lr 22 Transformer windings n 2; the bidirectional DC voltage source U 2's positive terminal and the switching transistor S 5's drain and switching transistor S The drain of 7 is connected, and the switching transistor is... S The source of 5 is respectively connected to the switching transistor. S 6 drain and resonant capacitor Cr 21 Cathode, resonant inductor Lr 22 The cathode is connected, and the resonant capacitor is connected. Cr 21 The positive terminal and the resonant inductor Lr 21 The cathodes are connected, and the resonant inductor is connected.Lr 21 The positive terminals are respectively connected to the resonant inductor Lr 22 Positive terminal, transformer winding n The positive terminals of 2 are connected, and the transformer windings are connected. n Cathode and resonant capacitor of 2 Cr 22 The positive terminal is connected, and the resonant capacitor is resonant. Cr 22 The cathodes are respectively connected to the switching transistor S 7 source and switch S The drains of the 8 transistors are connected, and the switching transistor is... S The source of 8 is connected to the switching transistor. S 6 source, bidirectional DC voltage source U The cathodes of 2 are connected; The port 3 circuit includes a bidirectional DC voltage source. U 3. Switching transistor S 9. Switching transistor S 10 Switching transistor S 11 Switching transistor S 12 Resonant capacitor Cr 31 Resonant inductor Lr 31 Resonant inductor Lr 32 Transformer windings n 3; the bidirectional DC voltage source U 3's positive terminal and the switching transistor S 9 drain and switching transistor S 11 The drains are connected, and the switching transistor is switched. S The source of 9 is connected to the switching transistor. S 10 Drain and resonant capacitor Cr 31 Cathode, resonant inductor Lr 32 The cathode is connected, and the resonant capacitor is connected. Cr 31 The positive terminal and the resonant inductor Lr 32 The cathodes are connected, and the resonant inductor is connected. Lr 31 The positive terminals are respectively connected to the resonant inductor Lr 32 Positive terminal, transformer winding n The positive terminals of terminals 3 are connected, and the transformer windings are connected. n 3. Cathode and resonant capacitor Cr 32 The positive terminal is connected, and the resonant capacitor is resonant.Cr 32 The cathodes are respectively connected to the switching transistor S 11 source and switch S 12 The drains are connected, and the switching transistor is switched. S 12 The source of each transistor is connected to the switching transistor. S 10 Source, bidirectional DC voltage source U The cathode of 3 is connected.

[0006] Preferably, the switching transistor S 1- S 12 All transistors use MOSFETs, and the gate of each MOSFET is connected in series with a drive resistor. The resistance value of the drive resistor is in the range of 10Ω-100Ω, which is used to limit the gate drive current and prevent the switching transistor from being damaged due to excessive drive current.

[0007] Preferably, the transformer winding n 1. n 2. n All three are made of multi-strand stranded copper wire with a wire diameter ranging from 0.1mm to 1mm, which reduces losses caused by the skin effect and improves the energy transmission efficiency of the transformer.

[0008] Preferably, the transformer winding n 1. n 2. n The turns ratios of the three transformers are equal, ranging from 1:1 to 10:1. The transformers are high-frequency isolation transformers with ferrite cores, which improve the isolation performance and energy transmission efficiency of the circuit.

[0009] Preferably, the bidirectional DC voltage source U 1. U 2. U The output voltage of the three bidirectional DC voltage sources is adjustable, with an adjustable range of 0-1000V, and the output voltage of the three sources can be adjusted independently to adapt to different load requirements.

[0010] Preferably, the switching transistor S 1 and S 2. S 3 and S 4. S 5 and S 6. S 7 and S 8. S 9 and S 10 , S 11 and S12 Two complementary switch pairs are formed, with each pair having opposite on and off states, and the on-time difference controlled within 1μs-10μs to prevent short circuits caused by simultaneous on-time of both pairs.

[0011] Preferably, the resonant capacitor Cr 11 With resonant inductor Lr 11 , Lr 12 Forming the first resonant branch, the resonant capacitor Cr 12 With resonant inductor Lr 11 , Lr 12 This forms the second resonant branch; similarly, Cr 21 , Lr 21 , Lr 22 This forms the third resonant branch. Cr 22 , Lr 21 , Lr 22 This forms the fourth resonant branch; Cr 31 , Lr 31 , Lr 32 This forms the fifth resonant branch. Cr 32 , Lr 31 , Lr 32 This forms the sixth resonant branch. All six resonant branches have the same resonant frequency, ranging from 10kHz to 1MHz.

[0012] Preferably, the switching transistor S 1- S 12 A freewheeling diode is connected in parallel between the source and drain of the transistor. This freewheeling diode is a fast recovery diode with a reverse recovery time of less than 100ns. It is used to absorb the reverse voltage spike generated when the switching transistor is turned off, thus protecting the switching transistor. Preferably, the bidirectional DC voltage source U 1. U 2. UAll three adopt a full-bridge rectifier bidirectional power supply structure, with internally integrated filter capacitors and filter inductors. The capacitance value of the filter capacitors ranges from 100μF to 1000μF, and the inductance value of the filter inductors ranges from 10μH to 100μH, which are used to filter out ripple in the power supply output and ensure the stability of the power supply output voltage.

[0013] A control method for a novel multi-resonant three-port converter that simultaneously transmits fundamental and third harmonic energy is disclosed. This method, applied to the aforementioned novel multi-resonant three-port converter, includes the ability to transform the equivalent circuit into a Y-type equivalent circuit and a Δ-type equivalent circuit. The specific description is as follows: S1、 Z The Y-type equivalent circuit diagram when 1≠0, and the equivalent impedance of the resonant cavity at each port is as follows: ; in, Z kf This represents the equivalent impedance of port k at the fundamental frequency. Z kt This represents the impedance of port k at the third harmonic frequency. ω s It is the fundamental frequency angular velocity.

[0014] S2, Regarding the full-bridge output voltage u 1. u 2 and u 3. Perform a Fourier transform to obtain the expressions for its fundamental frequency and third harmonic, as shown in the following equations: ; Based on the above analysis, the resonant cavity impedance of port 1 when power decoupling is achieved at ports 2 and 3 can be obtained. Z The conditions that need to be met are as follows: ; Solving the above system of equations, we can obtain L r11 , C r11 , L r12 , C r12 The relationship between them:

[0015] ;

[0016] S3. Based on the Y-Δ transformation, the Δ-type equivalent circuit of the converter proposed in this invention can be obtained, wherein... Z 12f and Z 13t The expression for is shown in the following formula; the calculation methods for other impedances are the same as... Z 12f and Z 13t resemblance.

[0017] ; S4, when Z 1f and Z 1t When it is 0, at this time Z 32f and Z 32t The value is infinity. At this point, the transmission power between ports 2 and 3 is 0. At this point, the transmission power can be obtained. P 12 and P 13 The expression is as follows: ; in, M 2 and M The expression for 3 is as follows: .

[0018] The beneficial effects of this invention are as follows: 1. This invention can simultaneously realize the synchronous transmission of fundamental wave and third harmonic energy without the need to design separate transmission channels for different frequency powers, greatly simplifying the overall system topology; at the same time, relying on the precise parameter configuration of the resonant cavity to achieve power decoupling between each port, effectively suppressing power cross-coupling interference between the fundamental wave and the third harmonic, and improving the stability and reliability of multi-frequency power transmission. 2. This invention significantly improves power transmission capacity and spectrum utilization through the integrated transmission design of fundamental and third harmonic power, making it suitable for multi-frequency collaborative power supply application scenarios. The port power decoupling characteristic can weaken the mutual influence between the working states of each port, reduce control complexity, reduce investment in additional compensation devices, and facilitate the miniaturization and low-cost promotion and application of the device. Attached Figure Description

[0019] Figure 1 A novel multi-resonant three-port converter for simultaneous transmission of fundamental and third harmonic energy; Figure 2 The main waveform diagram of a novel multi-resonant three-port converter that transmits fundamental and third harmonic energy simultaneously; Figure 3 A schematic diagram of the equivalent circuit of a novel multi-resonant three-port converter (Y-Δ) that transmits fundamental and third harmonic energy simultaneously. Figure 4 for Z Y-type equivalent circuit diagram of a novel multi-resonant three-port converter that simultaneously transmits fundamental and third harmonic energy when 1≠0; Figure 5 for Z Δ-type equivalent circuit diagram of a novel multi-resonant three-port converter that transmits fundamental and third harmonic energy simultaneously when 1≠0; Figure 6 for Z Y-type equivalent circuit diagram of a novel multi-resonant three-port converter that transmits fundamental and third harmonic energy simultaneously when I=0; Figure 7 for Z The Δ-type equivalent circuit diagram of a novel multi-resonant three-port converter that transmits fundamental and third harmonic energy simultaneously when I=0; Figure 8 Y-type equivalent circuit diagram of a novel multi-resonant three-port converter that transmits fundamental and third harmonic energy simultaneously when Z1≠0; Figure 9 bidirectional voltage source U 1 = 110V U 2 = 60V U Simulink simulation waveform at 3=72V.

[0020] Explanation of the labels in the diagram: U 1. U 2. U Ports 1, 2, and 3 are bidirectional DC voltage sources, respectively. u 1. u 2. u 3 represents the full-bridge output voltages at ports 1, 2, and 3, respectively. S 1- S 12 It is a power switching device. C r11 , C r12 The resonant capacitor in the multi-element resonant cavity at port 1. L r11 , L r12 For the resonant inductor in the multi-element resonant cavity at port 1, C r21 , C r22 The resonant capacitor in the multi-element resonant cavity at port 2. L r21 , Lr22 For the resonant inductor in the multi-element resonant cavity at port 2, C r31 , C r32 This refers to the resonant capacitor in the multi-element resonant cavity at port 3. L r31 , L r32 For the resonant inductor in the multi-element resonant cavity at port 3, n 1. n 2. n 3 represents the three windings of the coupled inductor. d 1. d 2. d 3 represents the inner phase shift angle of the full-bridge circuit at ports 1, 2, and 3, respectively. φ 12 The phase difference between the output voltages of the full-bridge circuit at ports 1 and 2. φ 13 The phase difference between the output voltages of the full-bridge circuit at ports 1 and 2. u 1f , u 2f , u 3f These are the fundamental components of the output voltage of the full-bridge circuit at ports 1, 2, and 3, respectively. u 1t , u 2t , u 3t These are the third harmonic components of the output voltage of the full-bridge circuit at ports 1, 2, and 3, respectively. i r1 , i r2 , i r3 These are the resonant currents in ports 1, 2, and 3, respectively. V S1 - V S12 They are switching transistors S 1- S 12 The drive signal, i r2 ' , i r3 ' Indicates the resonant current i r2 , i r3 Converted to port 1 side, Z 1. Z 2. Z3 represents the equivalent impedance of the resonant cavity at ports 1, 2, and 3, respectively. Z 2 ' , Z 3 ' Indicates equivalent impedance Z 2. Z 3 times the value is calculated to port 1 side. Z 12 , Z 13 , Z 32 for Z 1. Z 2 ' , Z 3 ' Equivalent impedance after Y-Δ transformation. Detailed Implementation

[0021] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0022] like Figures 1-9 As shown in the figure, an embodiment of the present invention provides a novel multi-resonant three-port converter for simultaneous transmission of fundamental and third harmonic energy, comprising three independent port circuits, each port circuit being connected to a corresponding bidirectional DC voltage source. The specific connection structure is as follows: the three port circuits are port 1 circuit, port 2 circuit, and port 3 circuit; port 1 circuit includes a bidirectional DC voltage source. U 1. Switching transistor S 1. Switching transistor S 2. Switching transistor S 3. Switching transistor S 4. Resonant capacitor Cr 11 Resonant inductor Lr 11 Resonant inductor Lr 12 Transformer windings n 1; The bidirectional DC voltage source U 1's positive terminal and the switching transistor S 1's drain and switching transistor S The drains of transistor 3 are connected, and the switching transistor is... S The source of 1 is connected to the switching transistor. S 2's drain and resonant capacitor Cr 11 Cathode, resonant inductor Lr 12 The cathode is connected, and the resonant capacitor is connected. Cr 11 The positive terminal and the resonant inductor Lr 11 The cathodes are connected, and the resonant inductor is connected.Lr 11 The positive terminals are respectively connected to the resonant inductor Lr 12 Positive terminal, transformer winding n The positive terminal of 1 is connected to the transformer winding. n Cathode and resonant capacitor of 1 Cr 12 The positive terminal is connected, and the resonant capacitor is resonant. Cr 12 The cathodes are respectively connected to the switching transistor S 3's source and switch S The drains of 4 are connected, and the switching transistor is... S The source of 4 is connected to the switching transistor. S 2's source, bidirectional DC voltage source U The cathode of port 1 is connected; the circuit of port 2 includes a bidirectional DC voltage source. U 2. Switching transistor S 5. Switching transistor S 6. Switching transistor S 7. Switching transistor S 8. Resonant capacitor Cr 21 Resonant inductor Lr 22 Resonant inductor Lr 22 Transformer windings n 2; the bidirectional DC voltage source U 2's positive terminal and the switching transistor S 5's drain and switching transistor S The drain of 7 is connected, and the switching transistor is... S The source of 5 is respectively connected to the switching transistor. S 6 drain and resonant capacitor Cr 21 Cathode, resonant inductor Lr 22 The cathode is connected, and the resonant capacitor is connected. Cr 21 The positive terminal and the resonant inductor Lr 21 The cathodes are connected, and the resonant inductor is connected. Lr 21 The positive terminals are respectively connected to the resonant inductor Lr 22 Positive terminal, transformer winding n The positive terminals of 2 are connected, and the transformer windings are connected. n Cathode and resonant capacitor of 2 Cr 22 The positive terminal is connected, and the resonant capacitor is resonant. Cr 22 The cathodes are respectively connected to the switching transistor S 7 source and switch SThe drains of the 8 transistors are connected, and the switching transistor is... S The source of 8 is connected to the switching transistor. S 6 source, bidirectional DC voltage source U The cathode of port 2 is connected; the circuit at port 3 includes a bidirectional DC voltage source. U 3. Switching transistor S 9. Switching transistor S 10 Switching transistor S 11 Switching transistor S 12 Resonant capacitor Cr 31 Resonant inductor Lr 31 Resonant inductor Lr 32 Transformer windings n 3; the bidirectional DC voltage source U 3's positive terminal and the switching transistor S 9 drain and switching transistor S 11 The drains are connected, and the switching transistor is switched. S The source of 9 is connected to the switching transistor. S 10 Drain and resonant capacitor Cr 31 Cathode, resonant inductor Lr 32 The cathode is connected, and the resonant capacitor is connected. Cr 31 The positive terminal and the resonant inductor Lr 32 The cathodes are connected, and the resonant inductor is connected. Lr 31 The positive terminals are respectively connected to the resonant inductor Lr 32 Positive terminal, transformer winding n The positive terminals of terminals 3 are connected, and the transformer windings are connected. n 3. Cathode and resonant capacitor Cr 32 The positive terminal is connected, and the resonant capacitor is resonant. Cr 32 The cathodes are respectively connected to the switching transistor S 11 source and switch S 12 The drains are connected, and the switching transistor is switched. S 12 The source of each transistor is connected to the switching transistor. S 10 Source, bidirectional DC voltage source U The cathode of 3 is connected.

[0023] Specifically, the switching transistorS 1- S 12 All transistors use MOSFETs, and each MOSFET's gate is connected in series with a drive resistor. The resistance value of the drive resistor ranges from 10Ω to 100Ω, used to limit the gate drive current and prevent damage to the switching transistor due to excessive drive current. The transformer windings... n 1. n 2. n All three are made of multi-strand stranded copper wire with a wire diameter ranging from 0.1mm to 1mm, which reduces losses caused by the skin effect and improves the energy transmission efficiency of the transformer.

[0024] It should be noted that the transformer windings n 1. n 2. n The turns ratios of the three transformers are equal, ranging from 1:1 to 10:1. The transformers are high-frequency isolation transformers with ferrite cores, which improve the isolation performance and energy transmission efficiency of the circuit.

[0025] In this invention, the bidirectional DC voltage source U 1. U 2. U The output voltage of the three bidirectional DC voltage sources is adjustable, with an adjustable range of 0-1000V, and the output voltages of the three sources can be independently adjusted to adapt to different load requirements. The switching transistor... S 1 and S 2. S 3 and S 4. S 5 and S 6. S 7 and S 8. S 9 and S 10 , S 11 and S 12 Two complementary switch pairs are formed, with each pair having opposite on and off states, and the on-time difference controlled within 1μs-10μs to prevent short circuits caused by simultaneous on-time of both pairs. The resonant capacitor... Cr 11 With resonant inductor Lr 11 , Lr 12 Forming the first resonant branch, the resonant capacitor Cr 12 With resonant inductor Lr 11 , Lr 12 This forms the second resonant branch; similarly, Cr21 , Lr 21 , Lr 22 This forms the third resonant branch. Cr 22 , Lr 21 , Lr 22 This forms the fourth resonant branch; Cr 31 , Lr 31 , Lr 32 This forms the fifth resonant branch. Cr 32 , Lr 31 , Lr 32 This forms the sixth resonant branch. All six resonant branches have the same resonant frequency, ranging from 10kHz to 1MHz. The switching transistor... S 1- S 12 A freewheeling diode is connected in parallel between the source and drain of the transistor. This freewheeling diode is a fast recovery diode with a reverse recovery time of less than 100ns. It is used to absorb the reverse voltage spike generated when the switching transistor is turned off, thus protecting the switching transistor. Specifically, the bidirectional DC voltage source U 1. U 2. U All three adopt a full-bridge rectifier bidirectional power supply structure, with internally integrated filter capacitors and filter inductors. The capacitance value of the filter capacitors ranges from 100μF to 1000μF, and the inductance value of the filter inductors ranges from 10μH to 100μH, which are used to filter out ripple in the power supply output and ensure the stability of the power supply output voltage.

[0026] A control method for a novel multi-resonant three-port converter that simultaneously transmits fundamental and third harmonic energy is disclosed. This method, applied to the aforementioned novel multi-resonant three-port converter, includes the ability to transform the equivalent circuit into a Y-type equivalent circuit and a Δ-type equivalent circuit. The specific description is as follows: S1、 Z The Y-type equivalent circuit diagram when 1≠0 corresponds to Figure 3 The equivalent impedance of the resonant cavity at each port is as follows: ; in, Z kf This represents the equivalent impedance of port k at the fundamental frequency. Zkt This represents the impedance of port k at the third harmonic frequency. ω s It is the fundamental frequency angular velocity.

[0027] S2, Regarding the full-bridge output voltage u 1. u 2 and u 3. Perform a Fourier transform to obtain the expressions for its fundamental frequency and third harmonic, as shown in the following equations: ; Based on the above analysis, the resonant cavity impedance of port 1 when power decoupling is achieved at ports 2 and 3 can be obtained. Z The conditions that need to be met are as follows: ; Solving the above system of equations, we can obtain L r11 , C r11 , L r12 , C r12 The relationship between them:

[0028] ;

[0029] S3. Based on the Y-Δ transformation, the Δ-type equivalent circuit of the converter proposed in this invention can be obtained as follows: Figure 3 As shown. Among them Z 12f and Z 13t The expression for is shown in the following formula; the calculation methods for other impedances are the same as... Z 12f and Z 13t resemblance.

[0030] ; S4, when Z 1f and Z 1t When it is 0, at this time Z 32f and Z 32t It is infinite. The equivalent circuit at this point is as follows: Figure 3 As shown. At this time, the transmission power between ports 2 and 3 is 0; At this point, the transmission power can be obtained. P 12 andP 13 The expression is as follows: ; in, M 2 and M The expression for 3 is as follows: .

[0031] This invention discloses a novel control signal for a multi-resonant three-port converter that simultaneously transmits fundamental and third harmonic energy. V S1 - V S12 Its control power switch S 1- S 12 The switching on and off of the bridge outputs a square wave voltage. u 1. u 2. u 3, u 1. u 2. u The fundamental component in 3 u 1f , u 2f , u 3f , u 1. u 2. u The third harmonic component in 3 u 1t , u 2t , u 3t The resonant current in ports 1, 2, and 3 i r1 , i r2 , i r3 Phase shift angle of the entire bridge at ports 1, 2, and 3 d 1. d 2. d 3. Outward phase angle φ 12 , φ 13 like Figure 2 As shown. Its equivalent circuit during operation can be transformed into a Y-type equivalent circuit and a Δ-type equivalent circuit, as described in detail below: Z The Y-type equivalent circuit diagram when 1≠0 corresponds to Figure 3 The equivalent impedance of the resonant cavity at each port is as follows: ; in,Z kf This represents the equivalent impedance of port k at the fundamental frequency. Z kt This represents the impedance of port k at the third harmonic frequency. ω s It is the fundamental frequency angular velocity.

[0032] according to Figure 2 The key waveforms in the diagram represent the full-bridge output voltage. u 1. u 2 and u 3. Perform a Fourier transform to obtain the expressions for its fundamental frequency and third harmonic, as shown in the following equations: ; The necessary condition for achieving power decoupling between ports 2 and 3 is that the resonant cavity of port 1 can resonate in series at both the fundamental frequency and the third harmonic frequency. In addition, to ensure efficient energy transfer, the resonant cavities of ports 2 and 3 need to be inductive at both the fundamental frequency and the third harmonic frequency. Once both conditions are met, power decoupling between ports 2 and 3 at the fundamental and third harmonic frequencies can be achieved. That is, when the transmitted power between ports 2 and 1 changes, the transmitted power at port 3 remains unaffected, and vice versa.

[0033] Based on the above analysis, the resonant cavity impedance of port 1 when power decoupling is achieved at ports 2 and 3 can be obtained. Z The conditions that need to be met are as follows: ; Solving the above system of equations, we can obtain L r11 , C r11 , L r12 , C r12 The relationship between them:

[0034] ;

[0035] Based on the Y-Δ transformation, the Δ-type equivalent circuit of the converter proposed in this invention can be obtained as follows: Figure 3 As shown. Among them Z 12f and Z 13t The expression for is shown in the following formula; the calculation methods for other impedances are the same as... Z 12f and Z 13tresemblance.

[0036] ; when Z 1f and Z 1t When it is 0, at this time Z 32f and Z 32t It is infinite. The equivalent circuit at this point is as follows: Figure 3 As shown in the figure. At this time, the transmission power between ports 2 and 3 is 0.

[0037] At this point, the transmission power can be obtained. P 12 and P 13 The expression is as follows: ; in, M 2 and M The expression for 3 is as follows: ; It should be noted that, Figure 4 bidirectional voltage source voltage U 1 = 110V U 2 = 60V U 3 = 72V. Figure 5 for P 12 =310W P 13 Voltage at 630W u 1. u 2. u 3 and current i r1 Waveform, in which u 1. u 2. u 3. Peak voltages are approximately 110V, 60V, and 72V respectively, and currents are... i r1 The amplitude is approximately 25.4A. Figure 6 for P 12 =310W P 13 Voltage at 630W u 1. Current i r1 , i r2 and i r3 Waveform, in which u 1. The peak voltage is approximately 110V, and the current is... ir1 , i r2 and i r3 The peak currents are approximately 25.4A, 22.3A, and 29.3A, respectively. Figure 7 for P 12 =510W P 13 Voltage at 630W u 1. u 2. u 3 and current i r1 Waveform, in which u 1. u 2. u 3. Peak voltages are approximately 110V, 60V, and 72V respectively, and currents are... i r1 The amplitude is approximately 28.3A. Figure 8 for P 12 =510W P 13 Voltage at 630W u 1. Current i r1 , i r2 and i r3 Waveform, in which u 1. The peak voltage is approximately 110V, and the current is... i r1 , i r2 and i r3 The peak currents are approximately 28.3A, 27.5A, and 29.3A, respectively. Figure 9 for P 12 Voltage when it suddenly changes from 310W to 510W u 1. Current i r1 , i r2 and i r3 Waveform, in which u The peak voltage remains constant at approximately 110V, and the current... i r1 The peak current changed from 25.4A to 28.3A. i r2 The peak current changed from 22.3A to 27.5A. i r3The peak current remained constant at approximately 29.3A, demonstrating the power decoupling capability of this invention.

[0038] The foregoing has only described certain exemplary embodiments of the present invention by way of illustration. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the foregoing drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A novel multi-resonant three-port converter that simultaneously transmits fundamental and third harmonic energy, characterized in that, It includes three independent port circuits, each of which is connected to a corresponding bidirectional DC voltage source. The specific connection structure is as follows: The three port circuits are port 1 circuit, port 2 circuit and port 3 circuit respectively; The port 1 circuit includes a bidirectional DC voltage source. U 1. Switching transistor S 1. Switching transistor S 2. Switching transistor S 3. Switching transistor S 4. Resonant capacitor Cr 11 Resonant inductor Lr 11 Resonant inductor Lr 12 Transformer windings n 1; The bidirectional DC voltage source U 1's positive terminal and the switching transistor S 1's drain and switching transistor S The drains of transistor 3 are connected, and the switching transistor is... S The source of 1 is connected to the switching transistor. S 2's drain and resonant capacitor Cr 11 Cathode, resonant inductor Lr 12 The cathode is connected, and the resonant capacitor is connected. Cr 11 The positive terminal and the resonant inductor Lr 11 The cathodes are connected, and the resonant inductor is connected. Lr 11 The positive terminals are respectively connected to the resonant inductor Lr 12 Positive terminal, transformer winding n The positive terminal of 1 is connected to the transformer winding. n Cathode and resonant capacitor of 1 Cr 12 The positive terminal is connected, and the resonant capacitor is resonant. Cr 12 The cathodes are respectively connected to the switching transistor S 3's source and switch S The drains of 4 are connected, and the switching transistor is... S The source of 4 is connected to the switching transistor. S 2's source, bidirectional DC voltage source U The cathode of 1 is connected; The port 2 circuit includes a bidirectional DC voltage source. U 2. Switching transistor S 5. Switching transistor S 6. Switching transistor S 7. Switching transistor S 8. Resonant capacitor Cr 21 Resonant inductor Lr 22 Resonant inductor Lr 22 Transformer windings n 2; The bidirectional DC voltage source U 2's positive terminal and the switching transistor S 5's drain and switching transistor S The drain of 7 is connected, and the switching transistor is... S The source of 5 is respectively connected to the switching transistor. S 6 drain and resonant capacitor Cr 21 Cathode, resonant inductor Lr 22 The cathode is connected, and the resonant capacitor is connected. Cr 21 The positive terminal and the resonant inductor Lr 21 The cathodes are connected, and the resonant inductor is connected. Lr 21 The positive terminals are respectively connected to the resonant inductor Lr 22 Positive terminal, transformer winding n The positive terminals of 2 are connected, and the transformer windings are connected. n Cathode and resonant capacitor of 2 Cr 22 The positive terminal is connected, and the resonant capacitor is resonant. Cr 22 The cathodes are respectively connected to the switching transistor S 7 source and switch S The drains of the 8 transistors are connected, and the switching transistor is... S The source of 8 is connected to the switching transistor. S 6 source, bidirectional DC voltage source U The cathodes of 2 are connected; The port 3 circuit includes a bidirectional DC voltage source. U 3. Switching transistor S 9. Switching transistor S 10 Switching transistor S 11 Switching transistor S 12 Resonant capacitor Cr 31 Resonant inductor Lr 31 Resonant inductor Lr 32 Transformer windings n 3; The bidirectional DC voltage source U 3's positive terminal and the switching transistor S 9 drain and switching transistor S 11 The drains are connected, and the switching transistor is switched. S The source of 9 is connected to the switching transistor. S 10 Drain and resonant capacitor Cr 31 Cathode, resonant inductor Lr 32 The cathode is connected, and the resonant capacitor is connected. Cr 31 The positive terminal and the resonant inductor Lr 32 The cathodes are connected, and the resonant inductor is connected. Lr 31 The positive terminals are respectively connected to the resonant inductor Lr 32 Positive terminal, transformer winding n The positive terminals of terminals 3 are connected, and the transformer windings are connected. n 3. Cathode and resonant capacitor Cr 32 The positive terminal is connected, and the resonant capacitor is resonant. Cr 32 The cathodes are respectively connected to the switching transistor S 11 source and switch S 12 The drains are connected, and the switching transistor is switched. S 12 The source of each transistor is connected to the switching transistor. S 10 Source, bidirectional DC voltage source U The cathode of 3 is connected.

2. The novel multi-resonant three-port converter for simultaneous transmission of fundamental and third harmonic energy according to claim 1, characterized in that, The switching transistor S 1- S 12 All transistors use MOSFETs, and the gate of each MOSFET is connected in series with a drive resistor. The resistance value of the drive resistor is in the range of 10Ω-100Ω, which is used to limit the gate drive current and prevent the switching transistor from being damaged due to excessive drive current.

3. A novel multi-resonant three-port converter for simultaneous transmission of fundamental and third harmonic energy as described in claim 1, characterized in that, The transformer winding n 1. n 2. n All three are made of multi-strand stranded copper wire with a wire diameter ranging from 0.1mm to 1mm, which reduces losses caused by the skin effect and improves the energy transmission efficiency of the transformer.

4. A novel multi-resonant three-port converter for simultaneous transmission of fundamental and third harmonic energy according to claim 1, characterized in that, The transformer winding n 1. n 2. n The turns ratios of the three transformers are equal, ranging from 1:1 to 10:

1. The transformers are high-frequency isolation transformers with ferrite cores, which improve the isolation performance and energy transmission efficiency of the circuit.

5. A novel multi-resonant three-port converter for simultaneous transmission of fundamental and third harmonic energy according to claim 1, characterized in that, The bidirectional DC voltage source U 1. U 2. U The output voltage of the three bidirectional DC voltage sources is adjustable, with an adjustable range of 0-1000V, and the output voltage of the three sources can be adjusted independently to adapt to different load requirements.

6. A novel multi-resonant three-port converter for simultaneous transmission of fundamental and third harmonic energy according to claim 1, characterized in that, The switching transistor S 1 and S 2. S 3 and S 4. S 5 and S 6. S 7 and S 8. S 9 and S 10 , S 11 and S 12 Two complementary switch pairs are formed, with each pair having opposite on and off states, and the on-time difference controlled within 1μs-10μs to prevent short circuits caused by simultaneous on-time of both pairs.

7. A novel multi-resonant three-port converter for simultaneous transmission of fundamental and third harmonic energy according to claim 1, characterized in that, The resonant capacitor Cr 11 With resonant inductor Lr 11 , Lr 12 Forming the first resonant branch, the resonant capacitor Cr 12 With resonant inductor Lr 11 , Lr 12 This forms the second resonant branch; similarly, Cr 21 , Lr 21 , Lr 22 This forms the third resonant branch. Cr 22 , Lr 21 , Lr 22 This forms the fourth resonant branch; Cr 31 , Lr 31 , Lr 32 This forms the fifth resonant branch. Cr 32 , Lr 31 , Lr 32 This forms the sixth resonant branch. All six resonant branches have the same resonant frequency, ranging from 10kHz to 1MHz.

8. A novel multi-resonant three-port converter for simultaneous transmission of fundamental and third harmonic energy according to claim 1, characterized in that, The switching transistor S 1- S 12 A freewheeling diode is connected in parallel between the source and drain of the transistor. The freewheeling diode is a fast recovery diode with a reverse recovery time of less than 100ns. It is used to absorb the reverse spike voltage generated when the switching transistor is turned off and to protect the switching transistor.

9. A novel multi-resonant three-port converter for simultaneous transmission of fundamental and third harmonic energy according to claim 1, characterized in that, The bidirectional DC voltage source U 1. U 2. U All three adopt a full-bridge rectifier bidirectional power supply structure, with internally integrated filter capacitors and filter inductors. The capacitance value of the filter capacitors ranges from 100μF to 1000μF, and the inductance value of the filter inductors ranges from 10μH to 100μH, which are used to filter out ripple in the power supply output and ensure the stability of the power supply output voltage.

10. A control method for a novel multi-resonant three-port converter that simultaneously transmits fundamental and third harmonic energy, applied to the novel multi-resonant three-port converter that simultaneously transmits fundamental and third harmonic energy as described in any one of claims 1-9, characterized in that, The control method for the novel multi-resonant three-port converter that simultaneously transmits fundamental and third harmonic energy includes the ability to convert the equivalent circuit into a Y-type equivalent circuit and a Δ-type equivalent circuit, as described in detail below: S1、 Z The Y-type equivalent circuit diagram when 1≠0, and the equivalent impedance of the resonant cavity at each port is as follows: ； in, Z kf This represents the equivalent impedance of port k at the fundamental frequency. Z kt This represents the impedance of port k at the third harmonic frequency. ω s It is the fundamental frequency angular velocity; S2, Regarding the full-bridge output voltage u 1. u 2 and u 3. Perform a Fourier transform to obtain the expressions for its fundamental frequency and third harmonic, as shown in the following equations: ； Based on the above analysis, the resonant cavity impedance of port 1 when power decoupling is achieved at ports 2 and 3 can be obtained. Z The conditions that need to be met are as follows: ； Solving the above system of equations, we can obtain L r11 , C r11 , L r12 , C r12 The relationship between them: ； ； ； S3. Based on the Y-Δ transformation, the Δ-type equivalent circuit of the converter proposed in this invention can be obtained, wherein... Z 12f and Z 13t The expression for is shown in the following formula; the calculation methods for other impedances are the same as... Z 12f and Z 13t resemblance; ； S4, when Z 1f and Z 1t When it is 0, at this time Z 32f and Z 32t The value is infinity. At this point, the transmission power between ports 2 and 3 is 0. At this point, the transmission power can be obtained. P 12 and P 13 The expression is as follows: ； in, M 2 and M The expression for 3 is as follows: 。

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