Multi-port wired and wireless composite converter based on alternating current bus and control method

Abstract

According to the converter, a power supply is connected with a first resonance network, an energy storage unit is connected with a second resonance network, and a transmitting coil is connected with a third resonance network and is connected with a multi-winding transformer through the third resonance network; the receiving coil is connected with the fourth resonance network; the first resonance network, the second resonance network and the third resonance network are all connected to the multi-winding transformer, the fourth resonance network is connected with a load, inductance and capacitance in the resonance networks are adjusted, and the resonance frequencies of the first to fourth resonance networks are configured to be the same as the switching frequency of the converter; the control method comprises the combination of inner phase shift control and outer phase shift control. By adopting the technical scheme, wired and wireless integrated electric energy interconnection among multiple ports can be realized; power decoupling can be realized between the ports, that is, when the transmission power of one of the two ports changes, power fluctuation of other ports cannot be caused.

Description

Technical Field

[0001] This invention relates to multi-terminal power interconnection technology, and more particularly to a multi-port wired-wireless hybrid converter and control method based on an AC bus. Background Technology

[0002] Distributed reconfigurable satellite systems are a future-oriented spacecraft architecture, composed of multiple modular spacecraft with varying functions as basic units, forming a fully functional system. CubeSats, as a type of micro / nano satellite, embody the principles of generalization and standardization, providing an effective and reliable solution for distributed reconfigurable satellite systems. CubeSat modules can be functionally divided into power supply modules and mission payload modules. Traditional CubeSats primarily use mechanical connections for inter-module power supply, which is advantageous in static operating modes. However, this leads to wear and tear during satellite reconfiguration, is time-consuming and risky, and is difficult to adapt to the dynamic changes in configuration caused by frequent switching between different operating modes. Wireless power transfer technology, with its non-contact operation and ease of dynamic adjustment, can effectively solve these problems and is significantly superior to traditional mechanical connection power supply methods in inter-module power transfer applications.

[0003] For distributed reconfigurable satellite systems, a dual-mode integrated power transmission mechanism is adopted, combining the advantages of both power supply methods: the CubeSat, which handles the power supply function, integrates photovoltaic arrays and battery packs, using wired connections for power conversion and transmission to improve efficiency; wireless power transmission is used between the power supply module and the mission payload module to adapt to the system's dynamic reconfiguration requirements. Traditional CubeSat wired power supply distributes power through a DC bus, employing a sequential switching shunt regulator architecture to establish power transmission paths between multiple DC ports. However, in the dual-mode power supply system, the transmission coils require an AC excitation power supply, which is fundamentally different from the traditional architecture.

[0004] In existing technical solutions, wired multi-port networks that can provide AC excitation mostly use transformers as power exchange hubs and cannot realize wireless power transmission functions. For existing multi-port wireless power interconnection systems, the use of a large number of coils not only occupies space but also causes cross-coupling between multiple coils, resulting in mutual power interference between the ports of the system and complicated control methods. Summary of the Invention

[0005] Purpose of the invention: This invention provides a multi-port wired-wireless hybrid converter and control method based on an AC bus, aiming to realize the hybridization of wired and wireless power transmission based on the multi-port network provided by this invention, while simultaneously achieving power decoupling between multiple ports; furthermore, it achieves zero-voltage switching of all switching transistors across the entire load range and full gain range.

[0006] Technical Solution: This invention provides a multi-port wired-wireless hybrid converter based on an AC bus, comprising: a power supply, a multi-winding transformer, an energy storage unit, a transmission coil unit, a load, and first to fourth resonant networks, wherein: the power supply is connected to the first resonant network and, through the first resonant network, to the multi-winding transformer; the energy storage unit is connected to the second resonant network and, through the second resonant network, to the multi-winding transformer; the transmission coil unit includes a transmitting coil and a receiving coil; the transmitting coil is connected to the third resonant network and, through the third resonant network, to the multi-winding transformer; the receiving coil is connected to the fourth resonant network and, through the fourth resonant network, to the load; the first, second, and third resonant networks are all connected to the multi-winding transformer, and the fourth resonant network is connected to the load.

[0007] Specifically, when the transmission coil unit includes multiple transmitting coils and multiple receiving coils, the multiple transmitting coils are connected in series and are connected together to a third resonant network; each receiving coil is connected to a corresponding fourth resonant network; when there are multiple power sources, each power source is connected to a corresponding first resonant network.

[0008] Specifically, the first resonant network is an LCL structure, including two inductors and one capacitor connected in a T-shape; the second resonant network is an LC structure, including a capacitor and an inductor connected in series; the third and fourth resonant networks are both LCC structures, including two capacitors and one inductor connected in a T-shape.

[0009] Specifically, it also includes a power conversion unit, which adopts a full-bridge circuit and consists of four switching transistors forming two pairs of upper and lower bridge arms. The power supply is connected to the first resonant network through the power conversion unit, the energy storage unit is connected to the second resonant network through the power conversion unit, and the receiving coil is connected to the corresponding fourth resonant network through the power conversion unit.

[0010] Specifically, there is no physical electrical connection between the transmitting coil and the receiving coil.

[0011] Specifically, the inductors and capacitors in the resonant network are configured such that the resonant frequencies of the first to fourth resonant networks are the same as the switching frequency of the converter.

[0012] Specifically, the resonant frequencies of the first to fourth resonant networks are the same as the switching frequency of the converter, including: The configuration conditions for the first resonant network are as follows: ω s L fi =1 / ω s C fi =ω s L pi (i=1,2,…,n), Where, ω s L represents the resonant angular frequency. fi L pi and C fi These represent two inductors and one capacitor in the i-th first resonant network. One end of each of the three components is connected to a single point, and the other ends are connected to the two ends of the power conversion unit and the transformer, respectively. The configuration conditions for the second resonant network are as follows: ω s L s =1 / ω s C s , Among them, L s and C s These represent the inductor and capacitor connected in series in the second resonant network, respectively. The configuration conditions for the third resonant network are as follows: ω s L f =1 / ω s C f =ω s Σ j=1 m L ij - 1 / ω s C p (j=1,2,…,m), Among them, L f C p and C f These represent an inductor and two capacitors in the third resonant network. One end of each of the three components is connected to a single point, and the other ends are connected to the transformer port and the two ends of the transmitting coil, respectively. L ij Let represent the self-inductance of the j-th transmitting coil among the m series-connected transmitting coils linked to the third resonant network; The configuration conditions for the fourth resonant network are as follows: ω s L foj =1 / ω s C foj =ω s L oj - 1 / ω s C poj , Among them, L foj C foj and C poj Let L represent an inductor and two capacitors in the j-th fourth resonant network, respectively. One end of each of the three components is connected to a single point, and the other ends are connected to the two ends of the power conversion unit and the receiving coil, respectively. oj This represents the self-inductance of the j-th receiving coil.

[0013] The present invention also provides a control method for a converter, used in any of the multi-port wired-wireless composite converters based on an AC bus provided by the present invention, comprising: the amplitude and phase of a constant AC bus voltage.

[0014] Specifically, the converter employs internal phase-shift control: the sampled voltage value of the port corresponding to the power supply, energy storage unit, or load is compared with the corresponding reference voltage value. If the sampled voltage value is higher than the reference voltage value, the internal phase-shift angle of the corresponding power conversion unit is increased; if the sampled voltage value is lower than the reference voltage value, the internal phase-shift angle of the corresponding power conversion unit is decreased; if the power supply is a photovoltaic cell, the internal phase-shift angle of the power conversion unit corresponding to the power supply is adjusted so that the power conversion unit corresponding to the power supply operates in maximum power point tracking mode.

[0015] Specifically, the external phase-shift control adopted by the converter is as follows: the external phase-shift angle of the power conversion unit corresponding to the power supply relative to the power conversion unit corresponding to the energy storage unit is greater than the sum of half of the internal phase-shift angle of the power conversion unit corresponding to the power supply and 90°; the external phase-shift angle of the power conversion unit corresponding to the energy storage unit relative to the power conversion unit corresponding to the load is greater than the sum of half of the internal phase-shift angle of the power conversion unit corresponding to the load and 90°.

[0016] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages: (1) It realizes wired and wireless dual-mode integrated power interconnection between multiple ports, which greatly improves the flexible power supply capability of the converter; (2) Power decoupling can be realized between all ports, and when the transmission power of two ports changes, it will not cause power fluctuations in other ports; (3) It can realize zero-voltage switching of all switching tubes in the full load range and full gain range, so that the converter can work at high switching frequency, which is conducive to improving power density; (4) The control method is simple, versatile and highly reliable. Attached Figure Description

[0017] Figure 1 A schematic diagram of the structure of the multi-port wired-wireless hybrid converter provided by the present invention; Figure 2 Here is a four-port circuit topology diagram of the converter based on the present invention; Figure 3 This is a block diagram of the four-port circuit control of the converter provided by the present invention; Figure 4 The following are the switching timing and key voltage and current waveforms of the four-port circuit of the converter provided by this invention; 1-Power supply; 2-Power conversion unit corresponding to the power supply; 3-First resonant network; 4-Multi-winding transformer; 5-Second resonant network; 6-Energy storage unit; 7-Third resonant network; 8-Transmission coil unit; 9-Fourth resonant network; 10-Load. Detailed Implementation

[0018] The technical solution of the present invention will be further described below with reference to the accompanying drawings.

[0019] See Figure 1 This is a schematic diagram of the structure of the multi-port wired-wireless composite converter provided by the present invention.

[0020] This invention provides a multi-port wired-wireless hybrid converter based on an AC bus, comprising: a power supply 1, a multi-winding transformer 4, an energy storage unit 6, a transmission coil unit 8, a load 10, and first to fourth resonant networks (3, 5, 7, and 9), wherein: the power supply 1 is connected to the first resonant network 3, and is connected to the multi-winding transformer 4 through the first resonant network 3; the energy storage unit 6 is connected to the second resonant network 5, and is connected to the multi-winding transformer 4 through the second resonant network 5; the transmission coil unit 8 includes a transmitting coil and a receiving coil, the transmitting coil is connected to the third resonant network 7, and is connected to the multi-winding transformer 4 through the third resonant network 7; the receiving coil is connected to the fourth resonant network 9, and is connected to the load 10 through the fourth resonant network 9; the first resonant network 3, the second resonant network 5, and the third resonant network 7 are all connected to the multi-winding transformer 4, and the fourth resonant network 9 is connected to the load 10.

[0021] In specific implementation, in the composite converter provided by this invention, the AC bus refers to the line at the transformer corresponding to the transmitting coil side.

[0022] In this embodiment of the invention, there is no physical electrical connection between the transmitting coil and the receiving coil.

[0023] In practice, wireless power transmission is achieved through the transmitting coil and receiving coil of the transmission coil unit.

[0024] In this embodiment of the invention, when the transmission coil unit includes multiple transmitting coils and multiple receiving coils, the multiple transmitting coils are connected in series and are connected together to a third resonant network; each receiving coil is connected to a corresponding fourth resonant network; when there are multiple power sources, each power source is connected to a corresponding first resonant network.

[0025] In practice, the number of transmitting coils and receiving coils is the same, and there is a one-to-one correspondence between the transmitting coils and the receiving coils.

[0026] In practice, when there are multiple transmitting coils, they are connected in series. One end of the first transmitting coil and one end of the last transmitting coil are connected to the circuit, and thus they are connected to a third resonant network.

[0027] In practice, when there are multiple receiving coils, there are usually multiple loads. Each receiving coil is connected to a corresponding fourth resonant network, and each load is also connected to a corresponding fourth resonant network. That is, the receiving coil, the fourth resonant network, and the load correspond one-to-one.

[0028] In this embodiment of the invention, the first resonant network is an LCL structure, including two inductors and one capacitor connected in a T-shape; the second resonant network is an LC structure, including a capacitor and an inductor connected in series; the third and fourth resonant networks are both LCC structures, including two capacitors and one inductor connected in a T-shape.

[0029] In this embodiment of the invention, a power conversion unit is also included. The power supply is connected to the first resonant network through the power conversion unit 2, the energy storage unit is connected to the second resonant network through the power conversion unit, and the receiving coil is connected to the corresponding fourth resonant network through the power conversion unit.

[0030] In practical implementation, the power conversion unit can be a full-bridge circuit structure. Each power conversion unit includes four switching devices, which form two pairs of upper and lower bridge arms. It supports bidirectional power conversion between DC-AC and AC-DC. Through high-frequency switching action, it achieves precise control of voltage and current. With the help of internal phase-shift control and external phase-shift control in the control method, it can achieve zero-voltage switching of all switching devices in the full load range and full gain range, enabling the converter to operate at high switching frequency, which is beneficial to improving power density.

[0031] See Figure 2 The circuit topology of the converter provided by the present invention is a four-port circuit diagram, wherein the number of transmitting coil, receiving coil and load are all 2.

[0032] like Figure 2 As shown, there is one power supply port, which can be used for an external photovoltaic cell and is denoted as port 1; the energy storage unit is a battery, and its port is denoted as port 2; the transformer port corresponding to the transmitting coil is denoted as port 3; and the ports of the two loads are denoted as output port 1 and output port 2, respectively. In this converter, there are four power conversion units, three transformer windings, two transmitting coils, two receiving coils, and two loads; one LCL resonant network, one LC resonant network, and three LCC resonant networks.

[0033] In specific implementation, such as Figure 2 As shown, the DC voltage at the power port (photovoltaic cell) is denoted as U. pv The current is ipv The input capacitor is C pv The corresponding voltage at the midpoint of the power conversion unit bridge arm is u. AB1 The switching device is S a1 To S a4 Resonant inductor L f1 The current on is i lf1 Resonant inductor L p1 The current on is i lp1 The DC voltage of the battery is denoted as U. bat The current is i bat The input capacitor is C bat The corresponding voltage at the midpoint of the power conversion unit bridge arm is u. AB2 The switching device is S b1 To S b4 The current in the resonant inductor L2 is i l2 Resonant inductor L f3 The current on is i lf3 Inductor L i1 and inductor L i2 The current on is i lp3 This includes the mutual inductance M1 between the first transmitting coil and the first receiving coil, and the mutual inductance M2 between the second transmitting coil and the second receiving coil; the DC voltage across the first load is denoted as U. o1 The current is i o1 The output capacitor is C o1 The load resistance is R o1 The corresponding voltage at the midpoint of the power conversion unit bridge arm is u. AB3 The switching device is S c1 To S c4 Resonant inductor L fo1 The current on is i lfo1 Inductor L o1 The current on is i lpo1 The DC voltage across the second load is denoted as U. o2 The current is i o2 The output capacitor is C o2 The load resistance is R o2 The corresponding voltage at the midpoint of the power conversion unit bridge arm is u. AB4 The switching device is S d1 To S d4 Resonant inductor L fo2 The current on is i lfo2 Inductor L o2 The current on is i lpo2 .

[0034] In this embodiment of the invention, the inductors and capacitors in the resonant network are configured such that the resonant frequencies of the first to fourth resonant networks are the same as the switching frequencies of the converter.

[0035] In practical implementation, by configuring the inductors and capacitors in the (first to fourth) resonant networks, the resonant frequencies of the first to fourth resonant networks are configured to be the same as the switching frequency of the converter, thereby achieving power decoupling between the three ports of the multi-winding transformer. Specifically, when the power transmitted between two ports is changed, the power of the third port will not change. There is no direct power exchange between the power supply port and the transmitting coil port. The power exchange between the three ports is achieved through the energy storage unit port. Therefore, when the load changes, the input power of the power supply port is not affected.

[0036] In this embodiment of the invention, the configuration conditions of the first resonant network are as follows: ω s L fi =1 / ω s C fi =ω s L pi (i=1,2), Where, ω s ω represents the resonant angular frequency. s It is also equal to the switching angular frequency of the converter, L fi L pi and C fi These represent two inductors and one capacitor in the i-th first resonant network. One end of each of the three components is connected to a single point, and the other ends are connected to the two ends of the power conversion unit and the transformer, respectively. The configuration conditions for the second resonant network are as follows: ω s L2=1 / ω s C2, Where L2 and C2 represent the inductor and capacitor connected in series in the second resonant network, respectively; The configuration conditions for the third resonant network are as follows: ω s L f3 =1 / ω s C f3 =ω s Σ j=1 m L ij - 1 / ω s C p3 (j=1,2), Among them, L f3 C p3 and C f3 These represent an inductor and two capacitors in the third resonant network. One end of each of the three components is connected to a single point, and the other ends are connected to the transformer port and the two ends of the transmitting coil, respectively. L ijLet represent the self-inductance of the j-th transmitting coil among the m series-connected transmitting coils linked to the third resonant network; The configuration conditions for the fourth resonant network are as follows: ω s L foj =1 / ω s C foj =ω s L oj - 1 / ω s C poj , Among them, L foj C foj and C poj Let L represent an inductor and two capacitors in the j-th fourth resonant network, respectively. One end of each of the three components is connected to a single point, and the other ends are connected to the two ends of the power conversion unit and the receiving coil, respectively. oj This represents the self-inductance of the j-th receiving coil.

[0037] The present invention also provides a control method for a converter for a multi-port wired-wireless hybrid converter based on an AC bus with multiple loads provided by the present invention, comprising: the amplitude and phase of a constant AC bus voltage.

[0038] In this embodiment of the invention, when there are multiple loads, the amplitude and phase of the AC bus voltage are kept constant, and changes in one load will not cause power fluctuations in other loads, thus achieving power decoupling between output ports.

[0039] See Figure 3 This is a four-port circuit control block diagram of the converter provided by the present invention.

[0040] In specific implementation, the phase shift angle of the full-bridge power conversion unit corresponding to the power supply port is denoted as φ1, the phase shift angle of the full-bridge power conversion unit corresponding to the energy storage unit port is denoted as φ2, the phase shift angle of the full-bridge power conversion unit corresponding to the first load port is denoted as φ3, the phase shift angle of the full-bridge power conversion unit corresponding to the second load port is denoted as φ4, the external phase shift angle between the full-bridge power conversion units corresponding to the power supply port and the energy storage unit port is denoted as α+π / 2, the external phase shift angle between the full-bridge power conversion units corresponding to the energy storage unit port and the first load port is denoted as β1+π / 2, and the external phase shift angle between the full-bridge power conversion units corresponding to the energy storage unit port and the second load port is denoted as β2+π / 2. The AC bus reference voltage is denoted as U. mref The reference voltage across the first load is denoted as U. o1ref The reference voltage across the second load is denoted as U. o2ref .

[0041] In this embodiment of the invention, the converter employs internal phase-shift control as follows: the sampled voltage value of the port corresponding to the power supply, energy storage unit, or load is compared with the corresponding reference voltage value. If the sampled voltage value is higher than the reference voltage value, the internal phase-shift angle of the corresponding power conversion unit is increased until the sampled voltage equals the corresponding reference voltage value; if the sampled voltage value is lower than the reference voltage value, the internal phase-shift angle of the corresponding power conversion unit is decreased until the sampled voltage equals the corresponding reference voltage value; if the power supply is a photovoltaic cell, the internal phase-shift angle of the power conversion unit corresponding to the power supply is adjusted so that the power conversion unit corresponding to the power supply operates in maximum power point tracking (MPPT) mode, and α is adjusted accordingly based on the real-time value of φ1 to make it slightly greater than φ1 / 2, ensuring that all switching transistors of the power conversion unit at the power supply port are in a zero-voltage switching state.

[0042] In this embodiment of the invention, the external phase shift control adopted for the converter is as follows: the external phase shift angle of the power conversion unit corresponding to the power supply relative to the power conversion unit corresponding to the energy storage unit is greater than the sum of half of the internal phase shift angle of the power conversion unit corresponding to the power supply and 90°; the external phase shift angle of the power conversion unit corresponding to the energy storage unit relative to the power conversion unit corresponding to the load is greater than the sum of half of the internal phase shift angle of the power conversion unit corresponding to the load and 90°.

[0043] In practical implementation, the control of inner and outer phase shifts is mainly aimed at composite converters equipped with power conversion units.

[0044] In practical implementation, the power conversion unit corresponding to the power supply port should be ahead of the power conversion unit corresponding to the energy storage unit port by a certain external phase shift angle (α+π / 2). Its value should be slightly greater than half of the internal phase shift angle of the power conversion unit corresponding to the power supply port and 90° (φ1 / 2+π / 2), that is, α>φ1 / 2+γ (γ represents the adjustment angle), so as to ensure that all the switching transistors of the power conversion unit of the power supply port achieve zero-voltage switching.

[0045] In specific implementation, the power conversion unit corresponding to the load port should lag the power conversion unit corresponding to the energy storage unit by a certain outward phase shift angle ((β1+π / 2), (β2+π / 2)). Its value should be slightly greater than half of the inward phase shift angle of the power conversion unit corresponding to the load port and 90° ((φ3 / 2+π / 2) and (φ4 / 2+π / 2)), that is, β1>φ3 / 2+γ, β2>φ4 / 2+γ, so as to ensure that all the switching transistors of the power conversion unit at the load port achieve zero-voltage switching.

[0046] In specific implementation, φ3 is adjusted according to the load size of the first load port to make the output port (first load port) work at the rated voltage. At the same time, β1 is adjusted according to the real-time value of φ3 to make it slightly greater than φ3 / 2, ensuring that all the switching transistors of the power conversion unit of the first load port are in the zero-voltage switching state. φ4 is adjusted according to the load size of the second load port to make the output port (second load port) work at the rated voltage. At the same time, β2 is adjusted according to the real-time value of φ4 to make it slightly greater than φ4 / 2, ensuring that all the switching transistors of the power conversion unit of the second load port are in the zero-voltage switching state.

[0047] In practical implementation, when the original external phase shift angle cannot meet the zero-voltage switching state of the power conversion unit switching transistors on the energy storage unit side, β1 and β2 are added. That is, according to the size of the internal phase shift angle of the corresponding power conversion unit of the energy storage unit, the external phase shift angles (β1+π / 2) and (β2+π / 2) can be added accordingly to ensure that all switching transistors of the power conversion unit at the energy storage unit port achieve zero-voltage switching.

[0048] In practical implementation, the converter provided by the present invention, under the control of the above method, can achieve zero-voltage switching of all switching transistors in the full load range and full gain range, enabling the converter to operate at high switching frequencies, which is beneficial to improving power density. Moreover, the control method is simple, versatile and highly reliable.

[0049] In practice, the above embodiment includes two loads (i.e., the first load and the second load). When the number of loads increases, the above embodiment can be adjusted accordingly.

[0050] In practice, the energy storage unit ports will automatically adjust the power flow direction and magnitude based on the power levels of the power supply port and the load port.

[0051] Based on the above control method, the converter includes the following operating modes: (1) When there is sufficient light and the load of the two load output ports is large, the power provided by the photovoltaic port alone is insufficient to meet the power of the output port. The converter will work in dual-source dual-load mode. At this time, the photovoltaic cell and the battery provide power together, and the first load port and the second load port output power to the load together. (2) When there is sufficient light and the load of the two load output ports is small, the power provided by the photovoltaic port is sufficient to meet the power of the output port and there is still redundancy. The converter will work in single-source three-load mode. At this time, only the photovoltaic cell provides power, the first load port and the second load port jointly output power to the load, and the energy storage port absorbs power. (3) When the light is too weak or there is no light, by increasing φ1 to 180°, the photovoltaic cell will no longer output power, and the converter will work in single-source dual-load mode. At this time, the energy storage unit provides power, and the first load port and the second load port jointly output power to the load. (4) When the light is weak and the first load port (or the second load port) is unloaded, increase φ3 (or φ4) to 180° so that the first load port (or the second load port) no longer outputs power. The converter will work in dual-source single-load mode. At this time, the photovoltaic cell and the energy storage unit provide power together, and only a single load port absorbs power. (5) When there is sufficient light and both load output ports are unloaded, increase φ3 and φ4 to 180° so that the first load port and the second load port no longer output power. The converter will work in single source single load mode. At this time, the photovoltaic cell provides power and the energy storage unit absorbs power.

[0052] See Figure 4 The diagram shows the switching timing and key voltage and current waveforms of the four-port circuit of the converter provided by this invention.

[0053] like Figure 4 The figure shows the midpoint voltage of each bridge arm and the current waveform flowing through the corresponding power conversion unit switch when the converter is operating in dual-source dual-load mode. The reference direction of each current is parallel to... Figure 2 The same as indicated by the label. The phase relationship between each port is as follows: Figure 4 As shown, power flows from the leading port to the lagging port. Since the energy storage unit port needs to be able to absorb and output power simultaneously, its phase should be between the phases of the power supply port and the load output port; for the power supply port, φ1 is inversely proportional to the light intensity; for the load output port, φ3 and φ4 are inversely proportional to the load.

[0054] In practical implementation, except for the energy storage unit port, the power of the other ports is determined by their own internal phase shift angle control, so the power of the energy storage unit port does not require additional control. When the power supply and load power change, the internal phase shift angle of their respective ports and the external phase shift angle between ports will be adjusted in real time, allowing the converter to switch freely between various operating modes.

Claims

1. A multi-port wired-wireless hybrid converter based on an AC bus, characterized in that, include: The power supply, multi-winding transformer, energy storage unit, transmission coil unit, load, and first to fourth resonant networks, wherein: The power supply is connected to the first resonant network and, through the first resonant network, to the multi-winding transformer; The energy storage unit is connected to the second resonant network, and is also connected to the multi-winding transformer through the second resonant network; The transmission coil unit includes a transmitting coil and a receiving coil. The transmitting coil is connected to a third resonant network and is connected to a multi-winding transformer through the third resonant network. The receiving coil is connected to a fourth resonant network and is connected to a load through the fourth resonant network. The first, second, and third resonant networks are all connected to the multi-winding transformer, and the fourth resonant network is connected to the load.

2. The multi-port wired-wireless hybrid converter based on an AC bus according to claim 1, characterized in that, There is no physical electrical connection between the transmitting coil and the receiving coil.

3. The multi-port wired-wireless hybrid converter based on an AC bus according to claim 1, characterized in that, When the transmission coil unit includes multiple transmitting coils and multiple receiving coils, the multiple transmitting coils are connected in series and are connected together to a third resonant network; each receiving coil is connected to a corresponding fourth resonant network. When there are multiple power sources, each power source is connected to a corresponding first resonant network.

4. The multi-port wired-wireless hybrid converter based on an AC bus according to claim 3, characterized in that, It also includes a power conversion unit, which adopts a full-bridge circuit and consists of two pairs of upper and lower bridge arms composed of four switching transistors. The power supply is connected to the first resonant network through the power conversion unit, the energy storage unit is connected to the second resonant network through the power conversion unit, and the receiving coil is connected to the corresponding fourth resonant network through the power conversion unit.

5. The multi-port wired-wireless hybrid converter based on an AC bus according to claim 4, characterized in that, The first resonant network is an LCL structure, including two inductors and one capacitor connected in a T-shape; the second resonant network is an LC structure, including a capacitor and an inductor connected in series; the third and fourth resonant networks are both LCC structures, including two capacitors and one inductor connected in a T-shape.

6. The multi-port wired-wireless hybrid converter based on an AC bus according to claim 5, characterized in that, The inductors and capacitors in the resonant network are configured such that the resonant frequencies of the first to fourth resonant networks are the same as the switching frequency of the converter.

7. The multi-port wired-wireless hybrid converter based on an AC bus according to claim 6, characterized in that, The resonant frequencies of the first to fourth resonant networks are the same as the switching frequencies of the converter, including: The configuration conditions for the first resonant network are as follows: oh s L fi =1 / h s C fi =ω s L pi ,(i=1,2,…,n), Where, ω s L represents the resonant angular frequency. fi L pi and C fi These represent two inductors and one capacitor in the i-th first resonant network. One end of each of the three components is connected to a single point, and the other ends are connected to the two ends of the power conversion unit and the transformer, respectively. The configuration conditions for the second resonant network are as follows: oh s L s =1 / h s C s , Among them, L s and C s These represent the inductor and capacitor connected in series in the second resonant network, respectively. The configuration conditions for the third resonant network are as follows: oh s L f =1 / h s C f =ω s S j=1 m L ij - 1 / h s C p ,(j=1,2,…,m), Among them, L f C p and C f These represent an inductor and two capacitors in the third resonant network. One end of each of the three components is connected to a single point, and the other ends are connected to the transformer port and the two ends of the transmitting coil, respectively. L ij Let represent the self-inductance of the j-th transmitting coil among the m series-connected transmitting coils linked to the third resonant network; The configuration conditions for the fourth resonant network are as follows: oh s L foj =1 / h s C foj =ω s L oj - 1 / h s C poj , Among them, L foj C foj and C poj Let L represent an inductor and two capacitors in the j-th fourth resonant network, respectively. One end of each of the three components is connected to a single point, and the other ends are connected to the two ends of the power conversion unit and the receiving coil, respectively. oj This represents the self-inductance of the j-th receiving coil.

8. A control method for a converter, characterized in that, A multi-port wired-wireless hybrid converter based on AC bus control according to any one of claims 3 to 7, comprising: The amplitude and phase of a constant AC bus voltage.

9. The control method for the converter according to claim 8, characterized in that, A multi-port wired-wireless hybrid converter based on an AC bus according to any one of claims 4 to 7, comprising: The converter employs internal phase-shift control: the sampled voltage value of the port corresponding to the power supply, energy storage unit, or load is compared with the corresponding reference voltage value. If the sampled voltage value is higher than the reference voltage value, the internal phase-shift angle of the corresponding power conversion unit is increased; if the sampled voltage value is lower than the reference voltage value, the internal phase-shift angle of the corresponding power conversion unit is decreased; if the power supply is a photovoltaic cell, the internal phase-shift angle of the power conversion unit corresponding to the power supply is adjusted so that the power conversion unit corresponding to the power supply operates in maximum power point tracking mode.

10. The control method for the converter according to claim 9, characterized in that, include: The external phase-shift control used in the converter is as follows: the external phase shift angle of the power conversion unit corresponding to the power supply relative to the power conversion unit corresponding to the energy storage unit is greater than the sum of half of the internal phase shift angle of the power conversion unit corresponding to the power supply and 90°; the external phase shift angle of the power conversion unit corresponding to the energy storage unit relative to the power conversion unit corresponding to the load is greater than the sum of half of the internal phase shift angle of the power conversion unit corresponding to the load and 90°.

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