Self-aligned wireless electric energy transmission system for rotating equipment and control method of self-aligned wireless electric energy transmission system

Abstract

The invention discloses a self-aligned rotating equipment wireless electric energy transmission system and a control method thereof. The system comprises a transmitting end and a receiving end, the transmitting end comprises a direct-current power supply, an inverter, a primary side compensation circuit and a transmitting coil which are connected in sequence; the receiving end comprises a first receiving module, a second receiving module and a load; the first receiving module and the second receiving module have the same structure, and each of the first receiving module and the second receiving module comprises a receiving coil, a secondary compensation circuit and a rectification filter circuit which are connected in sequence; the output end of the rectification filter circuit of the first receiving module and the output end of the rectification filter circuit of the second receiving module are connected in series and then are connected with a load. By judging the coupling voltage difference between the two receiving coils and the transmitting coil, the positions of the transmitting end and the receiving end are detected and adjusted, and the charging efficiency of the system is improved.

Description

Technical Field

[0001] This invention belongs to the field of wireless power transmission technology, specifically relating to a self-aligned wireless power transmission system for rotating equipment and its control method. Background Technology

[0002] Power supply issues for rotating equipment are prevalent in fields such as aerospace, oil drilling, and underwater vehicles. Traditional contact-based power supply methods suffer from problems such as easy wear and aging, and high failure rates, leading to reduced equipment reliability and limited lifespan. Wireless Power Transfer (WPT) technology, due to its contactless power transmission method, offers advantages such as safety, reliability, flexibility, convenience, and maintenance-free operation, providing an effective solution to the problem of stable power supply for rotating equipment.

[0003] However, in practical applications, the relative offset between the rotating and stationary sides is unavoidable. For example, in oil drilling equipment, there is a certain axial offset between the moving drill pipe and the stationary cylinder wall, resulting in low power transmission efficiency. Summary of the Invention

[0004] This invention is proposed to solve the problems existing in the prior art, and its purpose is to provide a self-aligned wireless power transmission system for rotating equipment and its control method.

[0005] This invention is achieved through the following technical solution: A self-aligned wireless power transmission system for rotating equipment includes a transmitter and a receiver. The transmitter includes a DC power supply, an inverter, a primary-side compensation circuit, and a transmitting coil connected in sequence. The receiver includes a first receiving module, a second receiving module, and a load. The first and second receiving modules have the same structure, each including a receiving coil, a secondary-side compensation circuit, and a rectifier and filter circuit connected in sequence. The output of the rectifier and filter circuit of the first and second receiving modules is connected in series to the load.

[0006] In the above technical solution, the transmitting end and the receiving end are positioned facing each other.

[0007] In the above technical solution, both the primary-side compensation circuit and the secondary-side compensation circuit adopt the LCC-S topology circuit.

[0008] In the above technical solution, the receiving end also includes two sets of sampling circuits. The sampling circuits collect the output voltage of the secondary compensation circuit of the first receiving module or the second receiving module. When the sampling voltages of the two sampling circuits are equal, the receiving coils of the first receiving module and the second receiving module are symmetrically arranged with the transmitting coil as the center.

[0009] In the above technical solution, both the transmitting coil and the receiving coil are arc-shaped DD-type coils; the sum of the lengths of the two receiving coils and the distance between the two receiving coils is equal to the length of the transmitting coil; the width of a single D-type coil of the receiving coil is the same as the width of a single D-type coil of the transmitting coil.

[0010] In the above technical solution, the transmitting end further includes a transmitting magnetic core; the transmitting magnetic core includes a magnetic core base plate and two magnetic core pillars disposed on the magnetic core base plate, the magnetic core base plate and the transmitting coil are stacked, and the two magnetic core pillars are respectively inserted into the two inner holes of the transmitting coil; the first receiving module and the second receiving module both further include a receiving magnetic core; the receiving magnetic core and the receiving coil are stacked.

[0011] In the above technical solution, the magnetic core column is located at the center of the inner hole of the transmitting coil, and is spaced apart from the two side walls of the inner hole along its length; the length of the magnetic core base plate is the same as the length of the magnetic core column, and the width is equal to the sum of the widths and the spacing between the two magnetic core columns.

[0012] In the above technical solution, an aluminum plate is provided on the side of the receiving magnetic core away from the receiving coil.

[0013] In the above technical solution, the transmitting coil and the transmitting magnetic core are stacked on the inner wall of the stator sleeve; the receiving coil and the receiving magnetic core are stacked on the outer wall of the rotor sleeve.

[0014] A control method for the aforementioned self-aligned wireless power transfer system for rotating equipment includes the following steps: S1. Initialize the primary circuit of the system and start contactless energy transfer; S2. The sampling circuit of the first receiving module and the sampling circuit of the second receiving module collect the output voltage Us1 of the secondary side compensation circuit of the first receiving module and the output voltage Us2 of the secondary side compensation circuit of the second receiving module in real time. S3. Determine whether |Us1-Us2| is less than the preset threshold α. If yes, the receiver stops moving and begins normal energy transmission; otherwise, proceed to step S4. S4. If Us1-Us2>α, then rotate to the right; if Us1-Us2<-α, then rotate to the left; and return to step S2.

[0015] The beneficial effects of this invention are: This invention provides a self-aligned wireless power transfer system for rotating equipment and its control method. By judging the coupling voltage difference between the two receiving coils, the position of the transmitting and receiving ends is detected and adjusted, thereby achieving proper alignment between the transmitting and receiving ends and improving the charging efficiency of the system. This application divides the receiving end into two groups of coils to ensure better anti-offset capability. Compared with existing control methods, the system control method of this application is not only simple and practical, but also does not require the addition of additional components. Attached Figure Description

[0016] Figure 1 This is a circuit diagram of the present invention; Figure 2 This is a schematic diagram of the assembly structure of the transmitting coil and the receiving coil in this invention; Figure 3 This is a schematic diagram of the transmitting coil in this invention; Figure 4 This is a schematic diagram of the structure of a pair of receiving coils in this invention; Figure 5 This is a graph showing the change in mutual inductance of the self-aligned coupler of the present invention. Figure 6 This is an equivalent circuit diagram of the self-aligned wireless power transfer system of the present invention; Figure 7 This is a diagram showing the relationship between the mutual inductances M1 and M2 and the y-dislocation of the present invention; Figure 8 This is a flowchart of the system control method of the present invention; Figure 9 This is a flowchart of the system parameter design method of the present invention; Figure 10 The sampling voltage U of this invention s1 and U s2 The relationship between y-displacement and the diagram; Figure 11 The waveforms of the output voltage and current at the receiving end under different loads are shown in the figure. Figure 12 This is a diagram showing the output current of the receiver under different y-offsets according to the present invention.

[0017] For those skilled in the art, other related figures can be obtained from the above figures without any creative effort. Detailed Implementation

[0018] To enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0019] Example 1 like Figures 1-4As shown, a self-aligned wireless power transmission system for rotating equipment includes a transmitter and a receiver. The transmitter and receiver are positioned opposite each other; the rotating parts of the transmitter and receiver are coaxially arranged, and the circuit board position can be designed arbitrarily. The transmitter includes a DC power supply U connected in sequence. dc Inverter, primary-side compensation circuit, transmitting coil L p and the transmitting magnetic core L d1 ; In this embodiment, the inverter is a full-bridge inverter, which includes four MOSFETs Q1 to Q4; the primary-side compensation circuit includes a primary compensation inductor L1, a first primary compensation capacitor C1, and a second primary compensation capacitor C. P The primary compensation inductor L1, the first primary compensation capacitor C1, and the second primary compensation capacitor C2 constitute an LCC topology circuit; the transmitting coil L... p It is a curved DD-type coil; The transmitting magnetic core L d1 It includes a magnetic core base plate and two magnetic core columns disposed on the magnetic core base plate. The magnetic core base plate is stacked with the transmitting coil, and the two magnetic core columns are respectively inserted into the two inner holes of the transmitting coil. The receiving end includes a first receiving module, a second receiving module, a first sampling circuit, a second sampling circuit, and a load; The first receiving module includes a first receiving coil L connected in sequence. s1 The first secondary-side compensation circuit and the first rectifier filter circuit; The second receiving module includes a second receiving coil L connected in sequence. s2 The second secondary compensation circuit and the second rectifier filter circuit; the output terminals of the first rectifier filter circuit and the second rectifier filter circuit are connected in series with the load R. L connect; The first secondary compensation circuit includes the primary compensation capacitor C. s1 ; The first rectifier and filter circuit includes D 1-1 ~D 1-4 There are a total of 4 diodes and filter capacitor C. d1 ; The second secondary-side compensation circuit includes a secondary compensation capacitor C. s2 ; The second rectifier and filter circuit includes D 2-1 ~D 2-4 There are a total of 4 diodes and filter capacitor C. d2 ; The first sampling circuit acquires the output voltage U of the first secondary compensation circuit. s1 ; The second sampling circuit acquires the output voltage and U of the second secondary-side compensation circuit. s2 ; First receiving coil L s1 Second receiving coil L s2 The receiving magnetic core L is evenly stacked. d2 ; transmitting coil L p and the transmitting magnetic core L d1 The first receiving coil L is stacked on the inner wall of the stator sleeve. s1 Second receiving coil L s2 With receiving magnetic core L d2 They are stacked on the outer wall of the rotor sleeve; In this embodiment, as Figure 2 and Figure 3 As shown, the transmitting magnetic core L d1 and receiving magnetic core L d2 All are ferrite cores to enhance magnetic coupling from the transmitter to the receiver; In this embodiment, the receiving magnetic core L d2 An aluminum plate is also provided on the side away from the coil to reduce leakage electromagnetic field; In this embodiment, the transmitting coil L p The receiving coil L is wound with 420 strands of Litz wire with a diameter of 3mm. s1 and L s2 All are wound with 200 strands of Litz wire with a diameter of 2mm; In this embodiment, as Figure 3 As shown, Figure 3 This is an unfolded diagram of the transmitting and receiving ends of the coupling mechanism. The transmitting coil L is shown after unfolding. p The length of the first receiving module and the length of the second receiving module are both l1, the distance between the first receiving module and the second receiving module is d1, and the lengths of the first receiving module and the second receiving module and the transmitting magnetic core are L. d1 The lengths of all coils are (l1-d1) / 2, and the transmitting coil L p The width of a single D-type coil and the receiving coil L s1 Receiver coil L s2 The width of a single D-type coil is l2, and the width of the core post is d2.

[0020] In this invention, both the transmitting and receiving coils are arc-surface DD-type coils. DD coils can improve the problem of mutual inductance changes caused by lateral offset, but their offset resistance is low and their offset tolerance range is small. Therefore, the coupling mechanism of this application improves the offset tolerance range of the magnetic coupling mechanism, such as... Figure 3 , 4 As shown, the transmitting magnetic core L d1It is positioned only in the center, protruding from its empty area; the interval between the first and second receiving modules is d1cm, and it is evenly distributed on the transmitting coil L. p Both sides of the central axis; transmitting coil L p With two receiving coils L s1 and L s2 The mutual inductance between them is M Lp_Ls1 and M Lp_Ls2 Define the axial direction of the rotating device as x, the radial direction as z, and the direction of the sleeve wall as y. The change in mutual inductance of the coils is consistent under different air gaps; therefore, z = 4 cm is set, and the change in mutual inductance of the simulated coupling mechanism is as follows: Figure 5 As shown.

[0021] Depend on Figure 5 It can be seen that when x = 0, M Lp_Ls1 and M Lp_Ls2 The mutual inductance changed from 0.24µH to 8.96µH, while M Lp_Ls (M) Lp_Ls =M Lp_Ls1 +M Lp_Ls2 The mutual inductance changes from 9.07 μH to 9.40 μH, i.e., -8cm≤y≤8cm, and the maximum mutual inductance difference in this region is 0.33 μH.

[0022] During the rotation of the rotor sleeve, when the sampling voltage U of the first sampling circuit and the second sampling circuit... s1 and U s2 When they are equal, the two receiving coils are symmetrical about the two ends of the transmitting coil, and the transmitting end and the receiving end are set facing each other.

[0023] To analyze the system, let: (1) First primary compensation capacitor C1, second primary compensation capacitor C P Secondary compensation capacitor C S Satisfy the following formula: (2) In the formula, ω is the operating angular frequency of power transmission, which satisfies ω=2πf, and f is the operating frequency of the system.

[0024] The operating principle of the circuit was analyzed using the First Harmonic Approximation (FHA) method. Based on the characteristics of the full-bridge inverter and full-bridge rectifier, the DC voltage U... dc With the inverter output AC voltage U in The relationship between the root mean square (RMS) values ​​can be expressed as: (3) When the rotor sleeve inside the rotating equipment enters the stator sleeve, it slowly extends into the charging area. The system is in self-calibration mode, and the equivalent circuit is as follows: Figure 6 As shown.

[0025] Using Kirchhoff's Voltage Law (KVL), and based on the relationship between the input and output voltages of the rectifier, the following equation can be derived: (4) In the formula, M1 and M2 are respectively M Lp_Ls1 and M Lp_Ls2 .

[0026] Then, substituting (2) and (3) into (4), we can get: (5) Further derivation yields: (6) In the formula, I s1 I s2 U s1 and U s2 They are respectively , , and The RMS value.

[0027] As can be seen from formula (6), U s1 and U s2 With parameters M1, M2, L1 and U respectively dc Related. When L1 and U dc Constant, the oscillations of M1 and M2 on the y-axis are as follows Figure 7 As shown, U s1 and U s2 There will also be corresponding fluctuations. This application utilizes this characteristic to detect and determine U. s1 and U s2 The size determines whether the coil is accurately aligned and the direction of offset.

[0028] Example 2 like Figure 8 As shown, a control method for a wireless power transfer system is provided for controlling the self-aligned wireless power transfer system described in Example 1. The specific steps are as follows: S1. Initialize the system transmitter circuit and start energy transfer; S2, the first sampling circuit and the second sampling circuit acquire voltage U in real time. s1 and U s2 ; S3, Judgment | U s1 -U s2Is it less than the preset threshold? If yes, the receiver stops moving and starts charging; otherwise, proceed to step S4. S4. If U s1 -U s2 > If U s1 -U s2 <- If the first value is not found, rotate to the left and return to step S2.

[0029] In this embodiment, a voltage difference |U is set. s1 -U s2 | The preset threshold is When the voltage difference |U s1 -U s2 |When the transmitter and receiver are facing each other, charging begins.

[0030] Example 3 like Figure 9 As shown, a parameter design method for a wireless power transmission system is used to design parameters for the wireless power transmission system described in Example 1. The specific steps are as follows: S1, Set DC voltage source U dc Operating frequency f, current I of the transmitting circuit P Load R L and the expected load voltage U L Load current I L And select transmitting coil L p The wire dimensions; S2. Calculate the primary compensation inductance value L1 according to equation (5), and calculate the value based on the desired output voltage U. L Formula (7) is used to calculate the transmitting coil L. p With receiving coil L S1 and L S2 The expected mutual inductances M'1 and M'2 are set, and the initial time of the transmitting coil L is determined. p Number of turns N P and receiving coil L S1 and L S2 Number of turns N s All are 1; S3. Determine whether the current mutual inductances M1 and M2 have reached the expected mutual inductances M'1 and M'2. If yes, proceed to step S5; otherwise, let N... P =N P +1、N s =N s +1, then judge the current mutual inductance M1 and M2; S4. Measure the current moment of the transmitting coil L. p and receiving coil Ls The self-induction value; S5. Set the interval d between the first receiving module and the second receiving module to 1; S6. Determine the current moment of the receiving coil L. s1 and L s2 Mutual induction M Ls1_Ls2 If the value approaches 0, proceed to step S7; otherwise, set d = d + 0.5 and proceed to step S3. S7. Calculate the compensation capacitors C1 and C2 according to equations (1) and (2). p and C s The value; In this embodiment, the parameters of the system described above are shown in Table 1, where N p N s They are 11 and 9 respectively. L1, L p The diameter is 3mm, L s The diameter is 2mm.

[0031] Table 1: System Parameters Experiments and simulations: Validation of the self-alignment method based on magnetic coupling structure: Due to the symmetry of the coupled structure, this application only tested the positive direction of the y-axis. Figure 10 The y-offset and U-offset are shown. s1 and U s2 The relationship. It can be seen that when the y-deviation approaches 0, |U s1 -U s2 The value also tends towards 0, indicating good device alignment. In the simulation, the error exponent α is set to 1V. Figure 11 The coupling mechanism is aligned with U. s1 and U s2 The waveform shows that the designed magnetic coupling mechanism achieves a y-axis alignment accuracy of 5mm, meaning that during the self-alignment process, the measured |U s1 -U s2 The voltage is 0.969V, indicating that the secondary side is well aligned.

[0032] Dynamic response verification under load changes: Figure 12 The output voltage and current waveforms at the transmitter and receiver are shown under different loads. The load is changed from 15Ω to 3.7Ω, and the output voltage U... L It varies between 46.3V and 45.3V, with a fluctuation range of approximately 2.2%.

[0033] In summary, this application utilizes a receiving coil to adjust the device position and also as an energy coil for wireless power transmission. A simulation model with an output current of 12A and an output voltage of 45V was established. The results show that the system can help adjust the position with a y-axis alignment accuracy of 5mm. When the load is changed from 15Ω to 3.7Ω, the output voltage U... L It varies between 46.3V and 45.3V, with a fluctuation range of approximately 2.2%.

[0034] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A self-aligned wireless power transmission system for rotating equipment, comprising a transmitter and a receiver; characterized in that: The transmitting end includes a DC power supply, an inverter, a primary-side compensation circuit, and a transmitting coil connected in sequence; the receiving end includes a first receiving module and a second receiving module with identical structures; both the first receiving module and the second receiving module include a receiving coil, a secondary-side compensation circuit, and a rectifier and filter circuit connected in sequence. The output terminals of the rectifier and filter circuits of the first receiving module and the second receiving module are connected in series and then connected to the load.

2. The self-aligned wireless power transmission system for rotating equipment according to claim 1, characterized in that: The transmitter and receiver are positioned facing each other.

3. The self-aligned wireless power transmission system for rotating equipment according to claim 1, characterized in that: Both the primary-side compensation circuit and the secondary-side compensation circuit adopt the LCC-S topology.

4. The self-aligned wireless power transmission system for rotating equipment according to claim 1, characterized in that: Each receiving end also includes two sets of sampling circuits. The sampling circuits collect the output voltage of the secondary compensation circuit of the first receiving module or the second receiving module. When the sampling voltages of the two sampling circuits are equal, the receiving coils of the first receiving module and the second receiving module are symmetrically arranged with the transmitting coil as the center.

5. The self-aligned wireless power transmission system for rotating equipment according to claim 1, characterized in that: Both the transmitting coil and the receiving coil are arc-shaped DD-type coils; the sum of the lengths of the two receiving coils and the distance between the two receiving coils is equal to the length of the transmitting coil; the width of a single D-type coil of the receiving coil is the same as the width of a single D-type coil of the transmitting coil.

6. The self-aligned wireless power transmission system for rotating equipment according to claim 1, characterized in that: The transmitting end also includes a transmitting magnetic core; The transmitting magnetic core includes a magnetic core base plate and two magnetic core pillars disposed on the magnetic core base plate. The magnetic core base plate is stacked with the transmitting coil, and the two magnetic core pillars are respectively inserted into the two inner holes of the transmitting coil. The first receiving module and the second receiving module both include a receiving magnetic core. The receiving magnetic core is stacked with the receiving coil.

7. The self-aligned wireless power transmission system for rotating equipment according to claim 6, characterized in that: The magnetic core column is located at the center of the inner hole of the transmitting coil, and is spaced apart from the two side walls along the longitudinal direction of the inner hole.

8. The self-aligned wireless power transmission system for rotating equipment according to claim 6, characterized in that: An aluminum plate is provided on the side of the receiving magnetic core away from the receiving coil.

9. The self-aligned wireless power transmission system for rotating equipment according to claim 6, characterized in that: The transmitting coil and transmitting magnetic core are stacked on the inner wall of the stator sleeve; the receiving coil and receiving magnetic core are stacked on the outer wall of the rotor sleeve.

10. A control method for a self-aligned wireless power transmission system for a rotating device as described in any one of claims 1 to 9, characterized in that: Includes the following steps: S1. Initialize the primary circuit of the system and start contactless energy transfer; S2. The sampling circuit of the first receiving module and the sampling circuit of the second receiving module collect the output voltage Us1 of the secondary side compensation circuit of the first receiving module and the output voltage Us2 of the secondary side compensation circuit of the second receiving module in real time. S3. Determine whether |Us1-Us2| is less than the preset threshold α. If yes, the receiver stops moving and begins normal energy transmission; otherwise, proceed to step S4. S4. If Us1-Us2>α, then rotate to the right; if Us1-Us2<-α, then rotate to the left; and return to step S2.

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