SWPDT system interference suppression method based on balanced impedance

Abstract

The invention discloses an SWPDT system interference suppression method based on balanced impedance, an SWPDT system comprises a primary side circuit and a secondary side circuit, and the primary side circuit comprises a direct current power supply, a direct current bus capacitor, a full bridge inverter, a primary side LCC compensation network, a transmitting coil with a tap and a signal transmitting circuit; the secondary circuit comprises a receiving coil with a tap, a secondary LCC compensation network, a signal receiving circuit, a full-bridge rectifier and a load; the method comprises the following steps of: equally dividing a compensation inductor, a series compensation capacitor and a parallel compensation capacitor in a primary side LCC compensation network and a secondary side LCC compensation network into two same parameter elements respectively; and connecting the two equally divided elements with the same parameter to the corresponding branches to form balanced impedance. According to the invention, differential-mode and common-mode conducted interference can be suppressed, and the anti-interference capability of the whole electromagnetic interference of the system can be improved.

Description

Technical Field

[0001] This invention relates to the field of wireless power transmission technology, and in particular to an interference suppression method for SWPDT systems based on balanced impedance. Background Technology

[0002] In magnetic-field coupled wireless power transfer (MC-WPT) systems, achieving efficient and stable operation often requires meeting various application requirements, including but not limited to closed-loop control optimization, real-time operational status monitoring, and foreign object detection. Therefore, establishing a stable communication link while transmitting power becomes a significant challenge in MC-WPT system design. To address this technical challenge, simultaneous wireless power and data transfer (SWPDT) technology has emerged. This technology achieves coordinated transmission of energy and data within the same coupled magnetic field channel, avoiding increased system complexity and cost associated with additional communication modules, while also effectively improving the overall system integration and reliability.

[0003] The circuit used in a typical SWPDT topology is an asymmetrical circuit. Parasitic parameters such as capacitance and inductance in the loop have a significant impact on the circuit impedance at high frequencies, and the circuit balance is often poor. Therefore, differential-mode and common-mode conducted interference will be generated, which will affect the signal and the overall electromagnetic interference immunity of the system. Summary of the Invention

[0004] This invention aims to at least partially solve the technical problems in related technologies. Therefore, the objective of this invention is to provide a balanced impedance-based SWPDT system interference suppression method, which can suppress differential-mode and common-mode conducted interference, while simultaneously improving the overall electromagnetic interference immunity of the system.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solution:

[0006] An interference suppression method for a balanced impedance-based SWPDT system, wherein the SWPDT system includes a primary-side circuit and a secondary-side circuit. The primary-side circuit includes a DC power supply, a DC bus capacitor, a full-bridge inverter, a primary-side LCC compensation network, a tapped transmitting coil, and a signal transmitting circuit. The secondary-side circuit includes a tapped receiving coil, a secondary-side LCC compensation network, a signal receiving circuit, a full-bridge rectifier, and a load. The method includes:

[0007] The compensation inductor, series compensation capacitor, and parallel compensation capacitor in the primary-side LCC compensation network and the secondary-side LCC compensation network are each divided into two components with the same parameters.

[0008] Connect the two identical components with the same parameters, after dividing them into equal parts, to the corresponding branches to form a balanced impedance.

[0009] In one possible implementation, in the original edge LCC compensation network,

[0010] The primary-side compensation inductor is divided into the first primary-side compensation inductor and the second primary-side compensation inductor, which are connected to the midpoints of the two bridge arms of the full-bridge inverter, respectively.

[0011] The primary-side series compensation capacitor is divided into a first primary-side series compensation capacitor and a second primary-side series compensation capacitor, which are connected to the two ends of the transmitting coil respectively.

[0012] The primary-side parallel compensation capacitors are divided into the first primary-side parallel compensation capacitor and the second primary-side parallel compensation capacitor, which are connected in series at the output of the full-bridge inverter.

[0013] In one possible implementation, in the secondary-side LCC compensation network,

[0014] The secondary-side compensation inductor is divided into a first secondary-side compensation inductor and a second secondary-side compensation inductor, which are respectively connected to the midpoints of the two bridge arms of the full-bridge rectifier.

[0015] The secondary-side series compensation capacitor is divided into a first secondary-side series compensation capacitor and a second secondary-side series compensation capacitor, which are connected to the two ends of the receiving coil respectively.

[0016] The secondary-side parallel compensation capacitors are divided into a first secondary-side parallel compensation capacitor and a second secondary-side parallel compensation capacitor, which are connected in series at the input terminal of the full-bridge rectifier.

[0017] In one possible implementation, the signal transmitting circuit includes a signal transmitting transformer and two sets of stacked metal plates. The method further includes connecting the primary coil of the signal transmitting transformer to a signal source, and connecting the two ends of the secondary coil of the signal transmitting transformer to one end of the transmitting coil and the middle tap, respectively, through the two sets of stacked metal plates.

[0018] In one possible implementation, the signal receiving circuit includes a signal receiving transformer and two other sets of stacked metal plates. The method further includes: connecting the primary winding of the signal receiving transformer in parallel with an RC network, and connecting the secondary winding of the signal receiving transformer to one end of the receiving coil and the middle tap through the other two sets of stacked metal plates.

[0019] In one possible implementation, the method further includes: connecting the first secondary-side parallel compensation capacitor and the second secondary-side parallel compensation capacitor in series and then grounding them.

[0020] In one possible implementation, the signal path formed by the signal transmitting circuit and the signal receiving circuit uses an EMI modulated signal.

[0021] In one possible implementation, the stacked metal plates are four-electrode metal plates, with each of the four coupling electrodes forming a coupling capacitor in pairs.

[0022] In one possible implementation, the SWPDT system employs dual-frequency LCC compensation to allow energy and signal to operate at different resonant points.

[0023] In one possible implementation, the components of the primary-side LCC compensation network and the secondary-side LCC compensation network are divided equally to form an EMI filter.

[0024] This invention has at least the following technical effects:

[0025] This invention provides an interference suppression method for SWPDT systems based on balanced impedance. This method introduces balanced impedance to evenly distribute the compensation element across each branch, achieving impedance balance and significantly suppressing the impact of differential-mode and common-mode conducted interference on the signal, thereby improving the signal transmission efficiency of the entire SWPDT system. Simultaneously, introducing a stacked metal plate coupling mechanism in the signal loop enhances the overall electromagnetic interference immunity of the system and simultaneously suppresses common-mode interference.

[0026] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the SWPDT system structure based on balanced impedance according to an embodiment of the present invention.

[0028] Figure 2(a) is a schematic diagram of the equivalent circuit model of the coupling mechanism in an embodiment of the present invention.

[0029] Figure 2(b) is a schematic diagram of the equivalent symmetrical capacitance model of the coupling mechanism in an embodiment of the present invention.

[0030] Figure 3 This is a schematic diagram of a stacked metal electrode plate according to an embodiment of the present invention.

[0031] Figure 4 This is a schematic diagram of the common-mode current on the receiving side of the signal channel before the introduction of a metal quadrupole plate in an embodiment of the present invention.

[0032] Figure 5 This is a schematic diagram of the common-mode current on the receiving side of the signal channel after the introduction of a metal quadrupole plate in an embodiment of the present invention.

[0033] Figure 6 This is a schematic diagram of the signal channel receiving demodulated signals without the introduction of a metal quadrupole plate in an embodiment of the present invention.

[0034] Figure 7 This is a schematic diagram of the signal channel receiving and demodulating signals after the introduction of a metal quadrupole plate in an embodiment of the present invention. Detailed Implementation

[0035] The following describes this embodiment in detail. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the invention, and should not be construed as limiting the invention.

[0036] The interference suppression method of the SWPDT system based on balanced impedance in this embodiment is described below with reference to the accompanying drawings.

[0037] Figure 1 This is a schematic diagram of a balanced impedance-based SWPDT system structure according to an embodiment of the present invention. Figure 1 As shown, the system includes a primary circuit and a secondary circuit. The primary circuit includes a DC power supply and a DC bus capacitor C. in A full-bridge inverter (composed of Q1 to Q4), a primary-side LCC (a type of resonant network structure) compensation network, and a tapped transmitting coil L. p The signal transmitting circuit; the secondary circuit includes a tapped receiving coil L. s Secondary-side LCC compensation network, signal receiving circuit, full-bridge rectifier (diodes D1-D4) and load R L The method includes:

[0038] Step S1: Divide the compensation inductor, series compensation capacitor and parallel compensation capacitor in the primary LCC compensation network and the secondary LCC compensation network into two components with the same parameters.

[0039] Step S2: Connect the two identical components with the same parameters after they have been divided equally to the corresponding branches to form a balanced impedance.

[0040] Specifically, in the primary-side LCC compensation network, the primary-side compensation inductor can be divided into the first primary-side compensation inductor L. f1 Second primary-side compensating inductor L f2 Each of these is connected to the midpoint of one of the two arms of the full-bridge inverter. The primary-side series compensation capacitor is equally divided into the first primary-side series compensation capacitor C. P1 Second primary-side series compensation capacitor C P2, respectively with transmitting coil L p The two ends are connected. The primary-side parallel compensation capacitor is equally divided into the first primary-side parallel compensation capacitor C. f1 The second primary-side parallel compensation capacitor C f2 It is connected in series at the output of the full-bridge inverter.

[0041] In a secondary-side LCC compensation network, the secondary-side compensation inductor can be divided into two equal parts: the first secondary-side compensation inductor L. f3 Second side compensation inductor L f4 Each of these is connected to the midpoint of one of the two arms of the full-bridge rectifier. The secondary-side series compensation capacitor is equally divided into the first secondary-side series compensation capacitor C. P3 The second secondary side series compensation capacitor C P4 , respectively with receiving coil L s The two ends are connected. The secondary parallel compensation capacitor is equally divided into the first secondary parallel compensation capacitor C. f3 The second-side parallel compensation capacitor C f4 It is connected in series at the input terminal of the full-bridge rectifier. The first secondary side has a parallel compensation capacitor C. f3 The second-side parallel compensation capacitor C f4 Connected in series and then grounded.

[0042] In one possible implementation, the signal transmitting circuit includes a signal transmitting transformer T1 and two sets of laminated metal plates, which can connect the primary coil of the signal transmitting transformer T1 to a signal source (the signal source voltage is U). d The signal transmitting transformer T1 is connected to the transmitting coil L via two sets of laminated metal plates at both ends of its secondary winding. p One end is connected to the center tap. The signal receiving circuit includes a signal receiving transformer T2 and two other sets of laminated metal plates. The primary winding of the signal receiving transformer T2 is connected in parallel with an RC (resistor-capacitor) network. The secondary winding of the signal receiving transformer T2 is connected to the receiving coil L through the other two sets of laminated metal plates. s One end is connected to the middle tap.

[0043] Specifically, the coupling mechanism of the SWPDT system with introduced balanced impedance is as follows: Figure 1 As shown, the energy path adopts a double-sided LCC circuit topology, while the signal path introduces a stacked metal plate. EMI (electromagnetic interference) modulation is used for the signal, and the signal transmission and power transmission share a coupling coil. In the energy circuit, the capacitance and inductance values ​​are equally distributed at the transmitting and receiving ends to achieve impedance balance, dynamically adapting to load changes. Dual-frequency LCC compensation is used to ensure that energy and signal operate at different resonant points, reducing mutual interference.

[0044] The stacked metal plates introduced in the signal loop are typical four-electrode metal plates. In a typical four-electrode coupling mechanism, the coupling electrodes form coupling capacitors between each other. Its six-capacitor equivalent circuit model is as follows: Figure 2a As shown. By studying the equivalent model of the electric field coupling mechanism, and to further illustrate the connection between the transmitting and receiving ends in the signal transmission loop, an equivalent π model of the coupling mechanism can be derived, as shown. Figure 2b As shown, the specific stacked metal electrode coupling mechanism is as follows: Figure 3 As shown.

[0045] exist Figure 2a In the middle, C ij For plate P i With P j The coupling capacitance between them. Specifically, the first to third capacitor parameters C1, C2, and C... M It can be represented as:

[0046]

[0047] The main transmission path of differential-mode interference current includes a series compensation inductor L f Parallel compensation capacitor C f The circuit and the series compensation inductor L f Series compensation capacitor C p and transmitting coil L p The circuit formed. Ideally, L f C f Constructing a low-pass filter, the resonant network exhibits very high impedance to high-frequency signals. However, due to the inductor winding process, inter-turn capacitance exists, and the capacitance model at high frequencies also includes lead inductance. These factors limit the resonant network's ability to impede high-frequency signals. Unlike the differential-mode path, common-mode interference follows a path with very low impedance: the loop formed by the right bridge arm output leads, the chassis, and the parasitic capacitances between the components and the chassis. Therefore, the resonant network constructed with this structure has very limited suppression of common-mode interference.

[0048] Therefore, the conducted interference suppression method of the MC-WPT system based on impedance balance characteristics provided in this embodiment has the following advantages: (1) Based on a typical bilateral LCC type resonant network, by connecting the primary side in series with the compensation inductor L f Two inductors L with identical parameters f1 and L f2 They are respectively placed at the output terminals of the left and right arms of the full-bridge inverter, and the primary-side series resonant capacitor C is connected in series. p Decomposed into two capacitors C with the same parameters p1 and C p2 and placed in series with the transmitting coil Lp On both sides, C is introduced into the two bridge arms of the full-bridge inverter. f1 and C f2 Two capacitors with the same parameters are used to obtain a symmetrical LCC type resonant network, which can balance the impedance of the left and right bridge arms, reduce the high-frequency harmonics of the inverter output differential mode voltage, suppress differential mode and common mode conducted interference, and will not affect the power transmission parameters of the system; (2) Based on the symmetrical LCC type resonant network, the capacitors with the same parameter values ​​C are further used to obtain a symmetrical LCC type resonant network. f3 With C f4 Perform the same operation on the secondary side, and change the capacitor C. f3 With C f4 The common terminal is connected to the chassis, i.e., ground, to further suppress the common-mode interference of the system without affecting the power transmission parameters of the system. (3) The introduction of a quadrupole coupling mechanism can effectively suppress the common-mode interference of the signal circuit.

[0049] To verify the feasibility and effectiveness of the SWPDT system interference suppression method based on balanced impedance proposed in this embodiment, a control simulation experimental setup was built. The system operates at a frequency of 85kHz, with a DC input voltage of 100V, and a 30Ω / 1kW power resistor as the load. The experimental setup mainly consists of a full-bridge inverter, a typical bilateral LCC resonant compensation network, a symmetrical LCC resonant and EMI filter fusion compensation network, a full-bridge rectifier filter circuit, and a load. The EMI filter is formed by equally dividing the components of the primary-side and secondary-side LCC compensation networks. A DC power supply, oscilloscope, differential voltage probe, and current probe constitute the system's power supply and measurement equipment.

[0050] In this embodiment, the four switching transistors of the inverter are closely attached to the aluminum profile heat sink to achieve good heat dissipation performance. The heat sink is connected to the casing (replaced by an aluminum plate in the experimental system) and together they are connected to ground to form a zero potential point. The series compensation inductor L in the primary and secondary resonant network... f Series compensation capacitor C p and parallel compensation capacitor C f The EMI filter, housed within the power electronic converter along with the circuit board, is integrated onto the PCB (printed circuit board) of the full-bridge inverter. Its parasitic parameters are rigorously controlled to achieve superior performance. The coupling coil is positioned on the outer surface of the housing and is isolated from the housing by a ferrite core.

[0051] Table 1 shows the simulation parameters of the SWPDT system.

[0052]

[0053] Among them, L p1 L p2L represents the self-inductance of the two parts of the transmitting coil, which are divided into two sections by the tap. s1 L s2 The self-inductances M and M are the two parts of the receiving coil divided by the tap. p1p2 M s1s2 M p1s1 M p2s2 M p1s2 M p2s1 These are the first to sixth mutual inductances between each pair of coils in the transmitting coil and the receiving coil, respectively. d f is the signal frequency. p R is the frequency of electrical energy. dout The load resistance is R. L .

[0054] Based on the simulation parameters from Maxwell (a professional electromagnetic field simulation software), the parameters of the four-plate capacitor were calculated to be C1 = 104.5 pF. M =30.2pF. A high-frequency SWPDT system conducted interference model was established by calculating the plate parameters and considering the high-frequency parasitic parameters of resistance, inductance, capacitance, and coupling coil. The waveforms of the common-mode current and demodulation voltage on the receiving side of the signal transmission channel were simulated with and without the metal plate, as shown below. Figures 4-7 .

[0055] Simulation results show that the introduction of metal plates significantly reduces glitches in the common-mode current waveform on the receiving side, protecting the electronic components of the signal channel. Furthermore, for the signal demodulation voltage, the introduction of metal plates greatly reduces common-mode interference in the signal transmission channel, thus ensuring correct signal demodulation. For the power transmission channel, the voltage change rate of the bridge arms is not constant. In the initial stage of the turn-off process, the voltage change rate of the two bridge arms is very low; in the middle stage of the turn-off process, the voltage change rate of the two bridge arms increases, generating a significant common-mode voltage; at the end of the turn-off process, the voltage change rate of the two bridge arms returns to the level at the initial turn-off stage. By splitting components to balance the impedance, CM (common-mode) noise can be effectively reduced.

[0056] In summary, the symmetrical LCC-S (resonant network structure) type resonant network proposed in this invention does not affect the power transmission parameters of the system, allowing for step-by-step parameter design and conducted EMI filter design, thus reducing the system's design complexity. The four-electrode metal plate introduced in the signal circuit of this invention can achieve common-mode conducted interference suppression and improve the overall electromagnetic interference immunity of the system. Furthermore, the system proposed in this invention exhibits low conducted interference characteristics, and the noise current amplitude in the coupling coil is significantly constrained, providing a favorable electromagnetic interference environment for the parallel transmission of power signals in the MC-WPT system.

[0057] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0058] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0059] Finally, it should be noted that the above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention should be considered equivalent substitutions and are included within the protection scope of the present invention.

Claims

1. A method for suppressing interference in a SWPDT system based on balanced impedance, characterized in that, The SWPDT system includes a primary-side circuit and a secondary-side circuit. The primary-side circuit includes a DC power supply, a DC bus capacitor, a full-bridge inverter, a primary-side LCC compensation network, a tapped transmitting coil, and a signal transmitting circuit. The secondary-side circuit includes a tapped receiving coil, a secondary-side LCC compensation network, a signal receiving circuit, a full-bridge rectifier, and a load. The method includes: The compensation inductor, series compensation capacitor, and parallel compensation capacitor in the primary-side LCC compensation network and the secondary-side LCC compensation network are each divided into two components with the same parameters. Then connect the two identical components with the same parameters after dividing them equally to the corresponding branches to form a balanced impedance.

2. The method as described in claim 1, characterized in that, In the original edge LCC compensation network The primary-side compensation inductor is divided into the first primary-side compensation inductor and the second primary-side compensation inductor, which are connected to the midpoints of the two bridge arms of the full-bridge inverter, respectively. The primary-side series compensation capacitor is divided into a first primary-side series compensation capacitor and a second primary-side series compensation capacitor, which are connected to the two ends of the transmitting coil respectively. The primary-side parallel compensation capacitors are divided into the first primary-side parallel compensation capacitor and the second primary-side parallel compensation capacitor, which are connected in series at the output of the full-bridge inverter.

3. The method as described in claim 1, characterized in that, In the secondary-side LCC compensation network The secondary-side compensation inductor is divided into a first secondary-side compensation inductor and a second secondary-side compensation inductor, which are respectively connected to the midpoints of the two bridge arms of the full-bridge rectifier. The secondary-side series compensation capacitor is divided into a first secondary-side series compensation capacitor and a second secondary-side series compensation capacitor, which are connected to the two ends of the receiving coil respectively. The secondary-side parallel compensation capacitors are divided into a first secondary-side parallel compensation capacitor and a second secondary-side parallel compensation capacitor, which are connected in series at the input terminal of the full-bridge rectifier.

4. The method as described in claim 1, characterized in that, The signal transmitting circuit includes a signal transmitting transformer and two sets of laminated metal plates, and the method further includes: The primary coil of the signal transmitting transformer is connected to the signal source, and the two ends of the secondary coil of the signal transmitting transformer are respectively connected to one end of the transmitting coil and the middle tap through two sets of stacked metal plates.

5. The method as described in claim 1, characterized in that, The signal receiving circuit includes a signal receiving transformer and two other sets of laminated metal plates, and the method further includes: The primary winding of the signal receiving transformer is connected in parallel with an RC network, and the secondary winding of the signal receiving transformer is connected to one end of the receiving coil and the middle tap through two other sets of stacked metal plates.

6. The method as described in claim 3, characterized in that, The method further includes: connecting the first secondary parallel compensation capacitor and the second secondary parallel compensation capacitor in series and then grounding them.

7. The method as described in claim 1, characterized in that, The signal path formed by the signal transmitting circuit and the signal receiving circuit uses an EMI modulation signal.

8. The method as described in claim 4 or 5, characterized in that, The stacked metal plate is a four-electrode metal plate, with each of the four coupling electrodes forming a coupling capacitor in pairs.

9. The method as described in claim 1, characterized in that, The SWPDT system employs dual-frequency LCC compensation to enable energy and signal to operate at different resonant points.

10. The method according to any one of claims 1-9, characterized in that, The components of the primary-side LCC compensation network and the secondary-side LCC compensation network are divided equally to form an EMI filter.

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