Wireless ultrasonic motor drive control system and operating method and drive control circuit

Abstract

This application relates to a highly integrated wireless ultrasonic motor system, comprising: a high-frequency inverter configured to convert DC power into high-frequency AC power; a first wireless power transmission channel and a second wireless power transmission channel respectively connected to the inverter, wherein the first wireless power transmission channel includes a first transmitting coil and a receiving coil directly connected to the stator of the motor, and the second wireless power transmission channel includes a second transmitting coil and a receiving coil directly connected to the stator, wherein, when excited by a high-frequency magnetic field, the stator resonates with these receiving coils to generate a driving AC voltage; an autonomous optimal frequency adaptive control unit configured to detect the zero-crossing point of the inverter output current and generate a drive trigger command for adjusting the motor drive frequency; and a frequency adaptive pulse step modulation unit configured to dynamically adjust the pulse step amplitude and frequency of the inverter output voltage.

Description

[0001] Cross-references to related applications

[0002] This application claims the benefit of U.S. Provisional Patent Application Serial No. 63 / 727,045, filed December 2, 2024, and U.S. Patent Application Serial No. 19 / 348,766, filed October 2, 2025, the disclosures of which are incorporated herein by reference in their entirety. Technical Field

[0003] This application generally relates to a drive control system and method for a wireless ultrasonic motor. More specifically, this application relates to a drive control system for a wireless ultrasonic motor (USM) with autonomous frequency adaptive pulse step modulation and the control of a highly integrated wireless ultrasonic motor system with autonomous frequency adaptive pulse step modulation. Background Technology

[0004] Wireless power transfer (WPT) is a revolutionary technology that allows electrical energy to be transmitted without physical connections or wires. This capability has been significantly developed, driven by advancements in electromagnetic theory and power electronics technology.

[0005] Two prominent technologies in the field of power transfer (WPT) are inductive power transfer (IPT) and capacitive power transfer (CPT), each employing different energy transfer principles. IPT relies on electromagnetic induction, where alternating current in the transmitting coil generates a magnetic field, which induces a current in the receiving coil, thus enabling energy transfer without physical connections. Due to its high efficiency and convenience over short distances, this method is widely used in consumer electronics, electric vehicle charging, and medical devices. Conversely, CPT operates through electric field coupling between two pairs of plates. When a high-frequency alternating voltage is applied to one plate, an induced voltage can be generated on the other plate. However, compared to IPT technology, the two pairs of coupled plates inevitably occupy more space, which is detrimental to integration and miniaturization.

[0006] In recent years, WPT technology has been extended to motor drive systems, which combine wireless power transmission with motor drive operation, enabling wireless power supply and wireless control of the motor without the need for physical connections, batteries, and controllers at the receiving end. This innovative approach eliminates the limitations of wired connections, increasing the flexibility of motor placement, especially in applications requiring mobility, such as in robot joints and electric vehicles. Furthermore, by removing physical connectors, wireless motor systems reduce electrical hazards and improve safety in environments where traditional wiring could pose risks.

[0007] Recent advances have led to the development of methods for wireless power supply and control of brushless DC motors, wireless switched reluctance motors, and wireless permanent magnet synchronous motors, enabling smooth motor operation and precise speed control. However, these wireless motors typically require complex peripheral circuitry, including multiple compensation components and semiconductor devices, which increases system complexity and maintenance costs. Furthermore, the coupling mechanisms are often bulky and heavy, hindering efforts towards miniaturization and integration.

[0008] A recent breakthrough involves wireless ultrasonic motor technology, which simplifies system architecture by eliminating the need for semiconductor devices at the receiver, thereby reducing complexity and cost. Wireless ultrasonic motors operate at high frequencies, allowing high-frequency AC power transmitted via the WPT method to be directly used to drive the motor without secondary energy conversion. However, wireless ultrasonic motor systems are inherently open-loop systems. It should be noted that the equivalent impedance of a wireless ultrasonic motor varies with operating time, load, temperature, and other factors. This variability causes the optimal driving frequency of the wireless ultrasonic motor to constantly change. However, the single resonant frequency of the WPT system makes it difficult for the wireless ultrasonic motor to operate stably at its peak performance, potentially jeopardizing the system's viability. Furthermore, a flexible voltage control method for driving wireless ultrasonic motors is lacking.

[0009] Despite the enormous potential of wireless ultrasonic motor systems, several challenges remain. To achieve widespread application, it is necessary to address the issues of adaptive control of the optimal drive frequency and stepless adjustment of the drive voltage at different drive frequencies. Summary of the Invention

[0010] This application provides a wireless ultrasonic motor system, with a particular focus on the design and control of a highly integrated wireless ultrasonic motor system. This system utilizes autonomous frequency adaptive pulse step modulation to automatically adjust the drive frequency and voltage of the wireless ultrasonic motor, thereby improving the performance of the wireless ultrasonic motor in various applications.

[0011] According to a first aspect of this application, a drive control circuit for a wireless ultrasonic motor is provided, the drive control circuit comprising: a high-frequency inverter configured to receive direct current (DC) power and convert the DC power into high-frequency alternating current (AC) power; and at least one power conversion stage comprising: a transmitter electrically connected to the high-frequency inverter, the transmitter comprising: a transmitting coil; and a compensation unit electrically connected between the high-frequency inverter and the transmitting coil, wherein the transmitter is configured to cause the transmitting coil to generate a high-frequency magnetic field in response to the high-frequency AC power; and a receiver comprising a receiving coil directly electrically connected to the stator of the wireless ultrasonic motor; wherein, in response to the high-frequency magnetic field generated by the transmitting coil, the receiving coil is configured to resonate with the stator, thereby generating a high-frequency AC voltage on the stator.

[0012] In an illustrative embodiment, the drive control circuit further includes an inductor connected in series with the receiving coil and / or a capacitor connected in parallel with the ultrasonic motor. In another preferred embodiment of this application, the receiving coil of the receiver is directly electrically connected to the stator of the ultrasonic motor.

[0013] In an illustrative embodiment, the drive control circuit further includes an additional power conversion stage electrically independent of the at least one power conversion stage, wherein the at least one power conversion stage and the additional power conversion stage have the same topology. Illustratively, the additional power conversion stage includes: an additional transmitter electrically connected to the high-frequency inverter, the additional transmitter including: an additional transmitting coil; and an additional compensation unit connected between the high-frequency inverter and the additional transmitting coil, wherein the additional transmitter is configured to cause the additional transmitting coil to generate an additional high-frequency magnetic field in response to the high-frequency AC power; and an additional receiver including an additional receiving coil directly electrically connected to the stator of the wireless ultrasonic motor; wherein, in response to the additional high-frequency magnetic field generated by the additional transmitting coil, the additional receiving coil is configured to resonate with the stator, thereby generating an additional high-frequency AC voltage on the stator.

[0014] Illustratively, the transmitting coil and the additional transmitting coil are stacked vertically to form a dual-coil structure, and the receiving coil and the additional receiving coil are stacked vertically to form an additional dual-coil structure. Illustratively, the compensation unit includes a compensation capacitor connected in series with the transmitting coil to form a series resonant circuit for providing resonance compensation; and the additional compensation unit includes an additional compensation capacitor connected in series with the additional transmitting coil to form an additional series resonant circuit for providing resonance compensation.

[0015] In an illustrative embodiment, the drive voltage applied by the high-frequency inverter to the at least one power conversion stage maintains a 90-degree phase difference with the drive voltage applied by the high-frequency inverter to the additional power conversion stage.

[0016] In an illustrative embodiment, the drive control circuit further includes an autonomous optimal frequency adaptive control unit configured to: detect a zero-crossing point of the inverter's output current; and, based on the detection of the zero-crossing point, generate a drive trigger command to trigger the inverter to adaptively adjust its frequency to operate autonomously at the optimal drive frequency of the wireless ultrasonic motor by maintaining the inverter's output voltage and output current substantially in phase. Illustratively, the autonomous optimal frequency adaptive control unit includes: a current sensor electrically connected to the inverter's output and configured to sample the inverter's output current; and a zero-crossing comparator communicatively coupled to the current sensor and configured to output the trigger command upon detecting a zero-crossing point of the sampled output current.

[0017] In a further illustrative or alternative embodiment, the drive control circuit includes a frequency adaptive pulse step modulation (FAPSM) unit configured to dynamically adjust the pulse step amplitude and frequency of the output voltage of the inverter, thereby providing stepless voltage control for the motor.

[0018] Illustratively, the FAPSM unit includes: modulator, the The modulator is configured to be based on the target voltage ratio ( Generates a pulse step modulation signal indicating whether a full-pulse step (F) or zero-pulse step (Z) is required; and a multiplier, the multiplier being connected to the... The modulator and the autonomous optimal frequency adaptive control unit are operatively coupled and configured to receive signals from the... The pulse step modulation signal from the modulator and the trigger command from the autonomous optimal frequency adaptive control unit are used to determine the switching mode of the high-frequency inverter.

[0019] Illustratively, the stated The modulator includes an adder configured to calculate the target voltage ratio. The input of the adder is the difference between the output (e) and the comparator output (y); an integrator configured to integrate the output (e) of the adder to produce an integral output (u); and a comparator configured to output a signal indicating the full-pulse step (F) if the integral output (u) exceeds 1; or output a signal indicating the zero-pulse step (Z) if the integral output (u) is less than 1; wherein the comparator output (y) is fed back to the input of the adder to form a closed-loop control of the voltage regulation.

[0020] According to a second aspect of this application, a wireless ultrasonic motor drive control system is provided, comprising: an ultrasonic motor; a high-frequency inverter configured to convert DC power into high-frequency AC power; a first wireless power transmission channel electrically connected to the inverter, the first wireless power transmission channel including a first transmitting coil electrically connected to the inverter via a first compensation unit and a first receiving coil electrically connected to the stator of the motor, wherein the first transmitting coil is configured to generate a high-frequency magnetic field in response to the high-frequency AC power; and a second wireless power transmission channel electrically connected to the inverter and electrically independent of the first wireless power transmission channel, the second wireless power transmission channel including a second transmitting coil electrically connected to the inverter via a second compensation unit and a first receiving coil electrically connected to the stator of the motor, wherein the first transmitting coil is configured to generate a high-frequency magnetic field in response to the high-frequency AC power; and a second wireless power transmission channel electrically connected to the inverter and electrically independent of the first wireless power transmission channel, the second wireless power transmission channel including a second transmitting coil electrically connected to the inverter via a second compensation unit and a first receiving coil electrically connected to the stator of the motor. The stator is electrically connected to a second receiving coil, wherein the second transmitting coil is configured to generate a high-frequency magnetic field in response to the high-frequency AC power, wherein, in response to the high-frequency magnetic field generated by the first transmitting coil and the second transmitting coil, the first receiving coil and the second receiving coil are configured to resonate with the stator, thereby generating a high-frequency AC voltage on the stator. An autonomous optimal frequency adaptive control unit is configured to detect the zero-crossing point of the inverter's output current and, based on the detection of the zero-crossing point, generate a drive trigger command to trigger the inverter to adaptively adjust its frequency to autonomously operate at the optimal drive frequency of the wireless ultrasonic motor by maintaining the inverter's output voltage and output current substantially in phase.

[0021] In an illustrative embodiment, the autonomous optimal frequency adaptive control unit includes: a current sensor electrically connected to the output of the inverter and configured to sample the output current of the inverter; and a zero-crossing comparator communicatively coupled to the current sensor and configured to output the trigger command when a zero-crossing point of the sampled output current is detected.

[0022] In a further illustrative or alternative embodiment, the wireless ultrasonic motor drive control system further includes a FAPSM unit configured to dynamically adjust the pulse step amplitude and frequency of the inverter's output voltage, thereby providing stepless voltage control for the motor.

[0023] Illustratively, the FAPSM unit includes: modulator, the The modulator is configured to be based on the target voltage ratio ( Generates a pulse step modulation signal indicating whether a full-pulse step (F) or zero-pulse step (Z) is required; and a multiplier, the multiplier being connected to the... The modulator and the autonomous optimal frequency adaptive control unit are operatively coupled and configured to receive signals from the... The pulse step modulation signal from the modulator and the trigger command from the autonomous optimal frequency adaptive control unit are used to determine the switching mode of the high-frequency inverter.

[0024] Illustratively, the stated The modulator includes an adder configured to calculate the target voltage ratio. The input of the adder is the difference between the output (e) and the comparator output (y); an integrator configured to integrate the output (e) of the adder to produce an integral output (u); and a comparator configured to output a signal indicating the full-pulse step (F) if the integral output (u) exceeds 1; or output a signal indicating the zero-pulse step (Z) if the integral output (u) is less than 1; wherein the comparator output (y) is fed back to the input of the adder to form a closed-loop control of the voltage regulation.

[0025] Illustratively, the first compensation unit includes a first compensation capacitor connected in series with a first transmitting coil to form a first series resonant circuit; and the second compensation unit includes a second compensation capacitor connected in series with a second transmitting coil to form a second series resonant circuit; and the driving voltage applied to the first wireless power transmission channel by the high-frequency inverter and the driving voltage applied to the second wireless power transmission channel by the high-frequency inverter maintain a 90-degree phase difference.

[0026] According to a third aspect of this application, a method is provided for initiating the operation of a wireless ultrasonic motor drive control system of the second aspect, the method comprising: (a) driving the wireless ultrasonic motor at a fixed rated drive frequency to establish a stable inverter output current; (b) after reaching the stable current, dynamically adjusting the drive frequency of the wireless ultrasonic motor based on real-time feedback of the inverter output current, and using coordinated variable frequency pulse step modulation to modulate the inverter output voltage to maintain phase alignment between the output voltage and the current, thereby transitioning to a FAPSM scheme.

[0027] Illustratively, driving the wireless ultrasonic motor at the fixed rated drive frequency includes setting the fixed rated drive frequency to match the resonant frequency of the wireless ultrasonic motor during startup, so as to generate a stable drive trigger command for initial current generation before transitioning to the FAPSM scheme.

[0028] Illustratively, the FAPSM scheme includes uniformly distributing positive and negative voltage pulses over multiple half-cycles to reduce current harmonics and oscillations.

[0029] According to a fourth aspect of this application, a drive control circuit for a wireless ultrasonic motor is provided, the drive control circuit comprising: a high-frequency inverter configured to receive a DC power supply and convert the DC power into high-frequency AC power; an integrated magnetic decoupler comprising: a first transmitting coil and a first receiving coil, and a second transmitting coil and a second receiving coil, wherein the first receiving coil and the second receiving coil are respectively directly connected to the stator of the wireless ultrasonic motor; a compensation topology connected to the high-frequency inverter and configured to generate a high-frequency magnetic field in the first transmitting coil and the second transmitting coil, wherein the first transmitting coil and the second transmitting coil respectively form part of a compensation unit; wherein, when excited by the high-frequency magnetic field, the first receiving coil and the second receiving coil are configured to resonate with the stator respectively, thereby generating a high-frequency AC voltage on the stator to drive the wireless ultrasonic motor.

[0030] In an illustrative embodiment, a first transmitting coil and a first receiving coil form a first dual-coil structure, and a second transmitting coil and a second receiving coil form a second dual-coil structure, each dual-coil structure comprising vertical stacking.

[0031] Illustratively, the first dual-coil structure transmits and receives magnetic energy independently of the second dual-coil structure, with no mutual magnetic interference between them; and the second dual-coil structure transmits and receives magnetic energy independently of the first dual-coil structure, with no mutual magnetic interference between them, such that the first transmitting coil couples energy only to the first receiving coil, and not to the second transmitting coil or the receiving coil; and the second transmitting coil couples energy only to the second receiving coil, and not to the first transmitting coil or the receiving coil.

[0032] Illustratively, the compensation topology includes: a first compensation capacitor connected in series with a first transmitting coil to form a first series resonant circuit; and a second compensation capacitor connected in series with a second transmitting coil to form a second series resonant circuit.

[0033] Illustratively, the high-frequency alternating current is supplied to the first transmitting coil via the first compensation capacitor and to the second transmitting coil via the second compensation capacitor, thereby inducing high-frequency magnetic fields in the first transmitting coil and the second transmitting coil, respectively.

[0034] In a further illustrative or alternative embodiment, the stator comprises a piezoelectric material with capacitive properties, such that the stator is electrically equivalent to a series combination of a capacitor and a resistor, such that when excited by a high-frequency magnetic field, the inductance of the first receiving coil and the second receiving coil and the equivalent capacitance of the stator form a series resonant circuit, thereby generating a high-frequency AC voltage on the stator.

[0035] In a further illustrative or alternative embodiment, the drive control circuit further includes an autonomous optimal frequency adaptive control unit configured to detect the zero-crossing point of the inverter output current in real time based on the change in the equivalent impedance of the stator, and generate a corresponding drive trigger command to adjust the drive frequency of the motor by triggering the inverter.

[0036] Advantageously, the autonomous optimal frequency adaptive control unit includes: a current sensor configured to sample the output current of the inverter; and a zero-crossing comparator configured to process the sampled output current and output a trigger command indicating when the output current crosses zero, thereby keeping the phases of the inverter output voltage and current aligned.

[0037] In an illustrative embodiment, the drive control circuit further includes a FAPSM unit configured to dynamically adjust the pulse step amplitude and frequency of the output voltage of the inverter, thereby providing stepless voltage control for the motor.

[0038] In a further illustrative or alternative embodiment, the FAPSM unit includes modulator, the The modulator is configured to be based on the target voltage ratio ( The inverter generates a pulse step signal and uses the drive trigger command to trigger the inverter, thereby implementing frequency adaptive pulse step modulation.

[0039] Advantageously, the drive trigger command from the autonomous optimal frequency adaptive control unit is integrated with a pulse step modulation signal to maintain frequency adaptive pulse step modulation at different drive frequencies and ensure phase alignment between the inverter output voltage and current.

[0040] In an illustrative embodiment, the FAPSM unit further includes a multiplier; and the The modulator includes an adder configured to calculate the target voltage ratio. The difference between the comparator output (y); an integrator configured to process the output (e) of the adder; and a comparator configured to: output an indication full-pulse step (F) if the output (u) of the integrator is greater than 1; or output a zero-pulse step (Z) if the output (u) of the integrator is less than 1, thereby forming a closed-loop control of the voltage regulation.

[0041] According to a fourth aspect of this application, a wireless ultrasonic motor drive control system is provided, comprising: an ultrasonic motor; a high-frequency inverter configured to convert direct current power into high-frequency alternating current power; a first wireless power transmission channel and a second wireless power transmission channel respectively connected to the inverter, wherein the first wireless power transmission channel includes a first transmitting coil and a first receiving coil directly connected to the stator of the motor, and the second wireless power transmission channel includes a second transmitting coil and a second receiving coil directly connected to the stator, and wherein the stator includes a piezoelectric material, which, when excited by a high-frequency magnetic field, interacts with the first and second receiving coils. The system generates a resonant current to produce a driving AC voltage; an autonomous optimal frequency adaptive control unit configured to detect the zero-crossing point of the inverter output current and generate a drive trigger command for adjusting the motor drive frequency; and a FAPSM unit configured to dynamically adjust the pulse step amplitude and frequency of the inverter output voltage to provide stepless voltage control for the motor; wherein the drive trigger command from the autonomous optimal frequency adaptive control unit is integrated with a pulse step modulation signal to maintain frequency adaptive pulse step modulation at different drive frequencies and ensure phase alignment between the inverter output voltage and current.

[0042] Advantageously, the first transmitting coil and the first receiving coil form a first dual-coil structure, and the second transmitting coil and the second receiving coil form a second dual-coil structure, each dual-coil structure comprising vertical stacking.

[0043] Advantageously, the first dual-coil structure transmits and receives magnetic energy independently of the second dual-coil structure, with no mutual magnetic interference between them; and the second dual-coil structure transmits and receives magnetic energy independently of the first dual-coil structure, with no mutual magnetic interference between them, such that the first transmitting coil couples energy only to the first receiving coil, and not to the second transmitting coil or the receiving coil; and the second transmitting coil couples energy only to the second receiving coil, and not to the first transmitting coil or the receiving coil.

[0044] In an illustrative embodiment, the autonomous optimal frequency adaptive control unit includes: a current sensor configured to sample the output current of the inverter; and a zero-crossing comparator configured to process the sampled output current and output a trigger command indicating when the output current crosses zero, thereby keeping the phases of the inverter output voltage and current aligned.

[0045] In an illustrative embodiment, the FAPSM unit includes modulator, the The modulator is configured to be based on the target voltage ratio ( The inverter generates a pulse step signal and uses the drive trigger command to trigger the inverter, thereby implementing frequency adaptive pulse step modulation.

[0046] Based on the above embodiments of this application, a highly integrated wireless ultrasonic motor system and drive control circuit are provided, which offer the following advantages:

[0047] 1. Employs a magnetically decoupled dual-coil configuration. Two vertically stacked coils are used to form an integrated magnetic decoupler (IMD) to effectively achieve magnetic decoupling by minimizing magnetic coupling between the two coils and improving power transmission efficiency.

[0048] 2. Extremely simplified receiver architecture, free of compensation components. The receiver operates without capacitors, sensors, semiconductors, encoders, or auxiliary circuitry. Instead, it utilizes the inherent capacitive characteristics of the wireless ultrasonic motor to form a resonant circuit with the receiving coil. This innovative approach eliminates traditional compensation networks, enabling a highly integrated and miniaturized design.

[0049] 3. Autonomous Optimal Frequency Adaptive Control Mechanism. Because the equivalent impedance of the wireless ultrasonic motor varies with load, temperature, and other factors, its optimal drive frequency also changes accordingly. Autonomous optimal frequency adaptive control enables the inverter to operate autonomously at the optimal drive frequency of the wireless ultrasonic motor. Inverter output current i ta The current sensor samples the signal, and a corresponding drive trigger command C is generated by a zero-crossing comparator. This command triggers the inverter switch. Therefore, even if the impedance of the wireless ultrasonic motor changes in real time, the inverter frequency can be adaptively adjusted to operate autonomously at the optimal drive frequency of the wireless ultrasonic motor by keeping the inverter output voltage and current in phase.

[0050] 4. FAPSM. Stepless adjustment of the inverter output voltage is crucial for flexible control of the speed of a wireless ultrasonic motor. Therefore, a frequency-adaptive pulse step modulation scheme is proposed. By controlling the pulse step of the inverter output voltage, the equivalent output voltage of the inverter can be steplessly adjusted. First, the target voltage ratio is... Input to In the modulator, a pulse step signal can then be generated. Finally, the drive trigger command C generated by the autonomous optimal frequency adaptive control triggers the pulse step signal to control the inverter, thereby realizing the inverter's frequency adaptive pulse step modulation. Attached Figure Description

[0051] The accompanying drawings, which are included in and form part of this specification, illustrate one or more embodiments of the invention and, together with the explanatory section, serve to explain the principles of the invention.

[0052] Figure 1 This is a system diagram of a wireless ultrasonic motor system with a highly integrated wireless power and drive system according to an embodiment of this application.

[0053] Figure 2 yes Figure 1 A simplified circuit diagram of the drive circuit for the wireless ultrasonic motor system of an embodiment.

[0054] Figure 3 yes Figure 2 The equivalent circuit diagram of the single-phase stator drive circuit of the embodiment.

[0055] Figure 4 Showing Figure 2 A further simplified equivalent circuit model of the single-phase drive circuit of the embodiment.

[0056] Figure 5 yes Figure 1 The equivalent circuit diagram of the single-phase stator drive circuit of the embodiment.

[0057] Figure 6 It is a display Figure 1 A diagram illustrating the construction of an integrated magnetic coupler.

[0058] Figure 7A This is a system diagram of a wireless ultrasonic motor system with a highly integrated wireless power and drive system according to another embodiment of this application.

[0059] Figure 7B yes Figure 7A The equivalent circuit diagram of the single-phase stator drive circuit of the embodiment.

[0060] Figure 8A This is a system diagram of a wireless ultrasonic motor system with a highly integrated wireless power and drive system, according to a further embodiment of this application.

[0061] Figure 8B yes Figure 8A The equivalent circuit diagram of the single-phase stator drive circuit of the embodiment.

[0062] Figure 9 This is a circuit diagram of a simplified drive circuit for a wireless ultrasonic motor system including an autonomous optimal frequency adaptive control system, according to a further embodiment of this application.

[0063] Figure 10 This is a diagram showing the four effective switching modes of a full-bridge inverter.

[0064] Figure 11 It is a state transition diagram that shows all possible state transitions and their corresponding voltage pulse ladders.

[0065] Figure 12 This is a schematic diagram of the full-pulse ladder "F" and the zero-pulse ladder "Z".

[0066] Figure 13 This is a schematic diagram of the FAPSM scheme.

[0067] Figure 14 The FASAM scheme is in = 0.2 to Waveform when = 0.8.

[0068] Figure 15 This is a waveform diagram of the output voltage and current of the A-phase inverter during the startup process of the wireless ultrasonic motor.

[0069] Figure 16A and Figure 16B They are shown respectively =1 and The output voltage and current of phase A inverter when =0.7.

[0070] Figure 17 It shows that for =0.6, the output voltage and current of phase A inverter when the equivalent capacitance of the wireless ultrasonic motor changes. Detailed Implementation

[0071] Referring now to embodiments of this application, wherein the accompanying drawings illustrate one or more embodiments. Reference numerals used repeatedly in this specification are used to indicate similar features or elements of this application. The following is provided to facilitate further understanding of this application by those skilled in the art, but does not limit the application in any way. It should be noted that those skilled in the art can make various modifications and alterations without departing from the concept of this application. For example, features shown or described as part of one embodiment may be used in conjunction with another embodiment to generate further implementations. Therefore, this application is intended to cover such variations and alterations within the scope of the appended claims and their equivalents.

[0072] This application introduces a highly integrated wireless ultrasonic motor system with autonomous frequency adaptive pulse step modulation, suitable for completely sealed environments or environments where traditional wiring is impractical. This section elaborates on the system architecture, operating principles, components, and potential applications, providing a comprehensive description of this application.

[0073] Figures 1 to 3 This application illustrates a first embodiment of a wireless ultrasonic motor system 100 with a highly integrated wireless power and drive mechanism. The system 100 features an extremely simplified receiver architecture, free of compensation components. The receiver operates without capacitors, sensors, semiconductors, encoders, or auxiliary circuitry, instead utilizing the inherent capacitive characteristics of the wireless ultrasonic motor to form a resonant circuit with the receiving coil. Traditional compensation networks are unnecessary.

[0074] like Figure 1 As shown, system 100 mainly includes: a wireless ultrasonic motor 110, two full-bridge inverters 120, and a transmitting coil L. ta 130 and L tb 130' and receiving coil L ra 140 and L rb 140', and the main compensation capacitor C ta 150 and C tb 160.

[0075] Figure 2 yes Figure 1 A simplified circuit diagram of the drive circuit for a wireless ultrasonic motor system is provided. Based on the physical structure of the wireless ultrasonic motor 110, the stator mechanical quantities can be equivalently converted into suitable electrical quantities through an equivalent circuit model. Therefore, the single-phase equivalent circuit of the proposed system 100 is as follows: Figure 3As shown, the wireless ultrasonic motor 110 is directly driven by orthogonal bipolar coils, and the simplified stator model of the wireless ultrasonic motor 110 is derived from L... m C d C m and R m The series and parallel connections constitute the system. It should be noted that, for the sake of simplifying the analysis, the UMS model does not consider load torque or other characteristics caused by pressure, temperature, and friction.

[0076] At a specific driving frequency, the stator of the wireless ultrasonic motor 110 is externally capacitive. For further simplification, the equivalent stator model can be simplified to a series connection of capacitor C' and resistor R', as follows: Figure 4 As shown, their values ​​can be derived as

[0077] Among them, the intermediate variable C p R can be represented as

[0078] in, .

[0079] The operating performance of the wireless ultrasonic motor 110 is highly dependent on the quality of the drive voltage, and high-order harmonics of the input voltage may be detrimental to its stable operation. Therefore, an impedance matching circuit is typically added before the stator to improve the operating characteristics of the wireless ultrasonic motor 110. In this application, the bipolar magnetic coupler 180 is used not only for wireless power and drive transmission but also as an inductive matching element for impedance matching of the wireless ultrasonic motor 110 to filter the input voltage, thereby improving load characteristics and drive capability.

[0080] according to Figure 4 The impedance on the receiver side can be expressed as

[0081] in, It is the operating angular frequency.

[0082] The reflected impedance from the receiver to the transmitter can be derived as follows:

[0083] Based on Kirchhoff's voltage law, the following equation can be obtained.

[0084] To maximize transmission efficiency, both the transmitter and receiver operate at their resonant frequencies. Therefore, the receiver inductance can be derived as follows:

[0085] Therefore, the output voltage URX can be calculated as follows:

[0086] The proposed drive topology enhances the voltage output, thereby facilitating the wireless drive of the wireless ultrasonic motor 110. By fully utilizing the capacitive characteristics of the wireless ultrasonic motor 110, the motor can be wirelessly driven using only a bipolar magnetic coupler 180. The receiver magnetic coupler not only serves for wireless power transmission but also resonates with the wireless ultrasonic motor 110 at a specific frequency to increase the drive voltage and compensate for the reactive power generated due to the capacitive nature of the wireless ultrasonic motor 110. Therefore, the receiver side can be completely sealed, resulting in better integration, higher robustness, and maintenance-free operation.

[0087] Figure 5 The equivalent circuit of phase A of the highly integrated wireless ultrasonic motor system 100 is shown. The wireless ultrasonic motor 110 operates as a two-phase motor, and since the equivalent circuit topology of phase B is the same as that of phase A, for simplicity, only the circuit topology of phase A is analyzed. Figure 5 In the configuration shown, Figure 1 The high-frequency inverter 120 depicted is equivalent to an AC voltage source u. in 120'. Transmitter component L ta and C ta A series resonant circuit is formed, which generates a high-frequency magnetic field in the transmitting coil 130.

[0088] At the receiving end, the stator of the wireless ultrasonic motor 110 is made of a piezoelectric material with capacitive properties, and can be represented as a series combination of capacitor C' and resistor R', such as... Figure 5 As shown. Under the excitation of the high-frequency magnetic field generated by the transmitting coil 130, the receiving coil L... ra The equivalent capacitance C' of the stator of the wireless ultrasonic motor 110 resonates in series with the stator of the 140, thereby generating a high-frequency AC voltage on the stator of the wireless ultrasonic motor 110. According to the inverse piezoelectric effect, this voltage causes the stator to vibrate. It should be noted that the compensation topology at the transmitter end is not limited to series compensation of inductors and capacitors. Those skilled in the art will recognize that various other compensation topologies can also be used at the transmitter end.

[0089] Therefore, for Figure 5 In the embodiments of this application shown, the relationship between the circuit parameters is as follows:

[0091] in, It is the angular frequency of the system at the resonant frequency, satisfying And f is the resonant frequency.

[0092] like Figure 1 As shown, the receiver of the system 100 is extremely simple. It fully utilizes the inherent capacitive characteristics of the wireless ultrasonic motor 110, allowing the wireless ultrasonic motor 110 to resonate with the receiving coils 140 and 140', thus enabling the wireless ultrasonic motor 110 to operate under the excitation of a high-frequency AC voltage generated through resonance. Furthermore, the receiver lacks external compensation components such as capacitors, sensors, semiconductors, encoders, and auxiliary circuits, significantly reducing system complexity and manufacturing costs.

[0093] Furthermore, the wireless ultrasonic motor 110 is a high-frequency AC motor, and the system is designed to resonate at a specific high frequency, typically in the range of tens to hundreds of kilohertz, depending on the characteristics of the wireless ultrasonic motor 110. The highly integrated wireless ultrasonic motor system 100 proposed in this application is not limited to motors with a specific frequency. Those skilled in the art will recognize that the inverter frequency of the system 100 proposed in this application can be changed to accommodate wireless ultrasonic motors 110 with different drive frequencies. In a two-phase configuration, phase A and phase B have the same topology, except that the drive voltages of these two phases maintain a 90-degree phase difference, thereby maximizing the torque output and speed characteristics of the wireless ultrasonic motor. This can be achieved by controlling the output voltages of the phase A and phase B inverters 120 to have a 90-degree phase difference.

[0094] Figure 6 A preferred embodiment of the coil is shown. For example... Figure 6 As shown, two orthogonal bipolar coils are used for simultaneous wireless power and drive transmission. These two orthogonal bipolar coils (i.e., a vertical bipolar coil (coil A) and a horizontal bipolar coil (coil B)) are designed for wireless power and drive transmission.

[0095] Preferably, the transmitting coils 130 and 130' and the receiving coils 140 and 140' are composed of four double-D coils. The first two double-D coils and the last two double-D coils are stacked together, and their positions are perpendicular to each other. The receiving coils 140 and 140' are formed and connected in the same way as the transmitting coils 130 and 130'. This coupling structure can transfer wireless energy to the target coil while greatly avoiding electromagnetic coupling with non-target coils. For example, transmitting coil A 130 is designed to transfer energy to receiving coil A 140, while it is not expected to transfer energy to transmitting coil B 130' and receiving coil B 140'.

[0096] Meanwhile, the transmitting coil B 130' is designed to transfer energy only to the receiving coil B 140', and not to the transmitting coil A 130 and the receiving coil A 140.

[0097] Therefore, the orthogonal overlapping structure makes the magnetic flux generated by coil A orthogonal to the magnetic flux generated by coil B, which means that the mutual inductance between the two coils is theoretically zero, thus achieving magnetic decoupling.

[0098] Therefore, transmitting coil A 130 and receiving coil A 140, as well as transmitting coil B 130' and receiving coil B 140', constitute a highly integrated magnetic coupler (IMC) 180, or integrated magnetic decoupler, i.e., IMD. In this application, both refer to the same topology.

[0099] Proper magnetic coupler design is crucial for the viable operation of WPT systems, especially for multi-channel transmission WPTs, as different coupler topologies induce magnetic flux in different directions. Bipolar coil design is highly advantageous for improving power transmission capability and coil misalignment tolerance. Furthermore, the integration of monopole and bipole coils facilitates multi-load wireless power transmission.

[0100] Figure 7A and Figure 7B Another embodiment of this application is shown. Specifically, Figure 7A A highly integrated wireless ultrasonic motor system 200 employing wireless power supply and drive mechanism is described. Figure 7B The equivalent circuit of phase A of a highly integrated wireless ultrasonic motor system 200 is shown.

[0101] and Figure 1 The embodiments shown are similar, with an extremely simplified receiver structure that omits power semiconductor devices, position sensors, and microcontrollers, thus significantly promoting high integration and maintenance-free operation. Figure 7A In the embodiment shown, capacitor C pa 282 is connected in parallel to the single-phase output side of the wireless ultrasonic motor 210. The principle behind this configuration is that if the equivalent capacitive reactance C' of the single-phase stator of the wireless ultrasonic motor 210 is very small, then the equivalent inductance L of the receiving coil 240... ra This would require a very large capacitor, which would increase the physical size of the receiving coil 240. Therefore, in this embodiment, capacitor C... pa 282 is connected in parallel to the single-phase output side of the wireless ultrasonic motor 210 to increase the equivalent capacitive reactance, thereby reducing the size of the receiving coil 240.

[0102] Figure 8A and Figure 8B Further embodiments of this application are shown. Specifically, Figure 8AA wireless ultrasonic motor system 300 employing a highly integrated wireless power supply and drive mechanism is described. Figure 8B The equivalent circuit of phase A of a highly integrated wireless ultrasonic motor system 300 is shown.

[0103] and Figure 1 and Figure 7A The illustrated embodiment is similar, with an extremely simplified receiver structure that omits power semiconductor devices, position sensors, and microcontrollers. This design significantly promotes high integration and maintenance-free operation. Figure 8A In the embodiment shown, inductor L sa 382 can be connected in series with receiving coil 340. The principle of this configuration is that if the equivalent capacitive reactance C' of the single-phase stator of the wireless ultrasonic motor 310 is very small, then the equivalent inductance L of receiving coil 340 will be much smaller. ra It will require a very large one. Therefore, the inductor L sa 382 can be connected in series with receiving coil 340 to reduce the size required for receiving coil 340 itself.

[0104] In summary, as shown in the above embodiments, the receiver side is very simple, without power semiconductors, position sensors, and microcontrollers, which greatly promotes high integration and maintenance-free operation.

[0105] Figure 9 Another embodiment of this application is shown, relating to a highly integrated wireless ultrasonic motor system 400 with autonomous frequency adaptive pulse step modulation. (With) Figure 1 The illustrated embodiment is similar, featuring a similar topology, designed to operate in a completely sealed environment without the need for a battery, power line, or controller at the receiver, and further includes autonomous frequency-adaptive pulse ladder modulation. Specifically, Figure 9 The equivalent circuit of phase A of a highly integrated wireless ultrasonic motor system 400 is shown. The system 400 includes a wireless ultrasonic motor 410, an inverter 420, a transmitting coil 430, a receiving coil 440, a transmitter compensation 450, a DC voltage source 460, and a current sampling circuit 472, as well as a controller and drive circuitry.

[0106] Figure 9 It further includes an autonomous optimal frequency adaptive control unit 470, which is configured to detect the zero-crossing point of the inverter output current and generate a drive trigger command for adjusting the motor drive frequency.

[0107] In a further preferred embodiment, in addition to the autonomous optimal frequency adaptive control unit 470, system 400 further includes a FAPSM unit 480 configured to dynamically adjust the pulse step amplitude and frequency of the output voltage of inverter 420, thereby providing stepless voltage control for the motor. The drive trigger command C from the autonomous optimal frequency adaptive control unit 470 is integrated with the pulse step modulation signal to maintain frequency adaptive pulse step modulation at different drive frequencies and ensure phase alignment between the inverter output voltage and current.

[0108] Figure 9 A schematic diagram of the autonomous optimal frequency adaptive control mechanism is further illustrated. Considering that the equivalent impedance of the wireless ultrasonic motor 410 changes due to factors such as load variations, temperature fluctuations, and operating time, the optimal drive frequency will continuously change. To address this issue, an autonomous optimal frequency adaptive control for the wireless ultrasonic motor 410 is proposed. Specifically, the system 400 uses a current sensor 472 to continuously monitor the output current of the A-phase inverter, and then uses a zero-crossing comparator 474 to detect when the current crosses zero, generating a trigger command C at the zero-crossing point. When the current crosses zero from negative to positive, pulse 1 is output; when the current crosses zero from positive to negative, pulse -1 is output. The rising and falling edges of the trigger command C trigger the operation of inverter switches S1, S2, S3, and S4. Therefore, the trigger command C provides the basis for frequency adjustment, ensuring that the output voltage and current remain in phase, thus operating at zero phase angle (ZPA). This is crucial for the optimal frequency adaptive control of the wireless ultrasonic motor 410, especially when the equivalent impedance of the wireless ultrasonic motor 410 changes.

[0109] Figure 10 The four effective switching modes of the full-bridge inverter 420 are demonstrated. Switching mode transitions can generate voltage pulse ladders. Figure 11 All possible state transitions and their corresponding voltage pulse steps are shown. The full-bridge inverter 420 can generate two voltage pulse steps: a full-pulse step and a zero-pulse step, where switching states "10" and "01" generate a full-pulse step, and states "00" and "11" generate a zero-pulse step. For example... Figure 12 As shown, "F" represents a full-pulse ladder, while "Z" represents a zero-pulse ladder.

[0110] Figure 13 A schematic diagram of a FAPSM 480 according to an embodiment of this application is shown. The FAPSM 480 modulator includes... Modulator 481 and multiplier 488. One of the inputs to adder 482 is a given target voltage ratio. Adder 482 calculation The difference between the output y from comparator 486 and the output signal y from comparator 486 generates an output signal e, which serves as the input to integrator 484. The output of the integrator (denoted as u) is fed to comparator 486. If u is greater than 1, comparator 486 outputs 1, indicating that a full-pulse step "F" is needed to increase the output voltage. Conversely, if u is less than 1, comparator 486 outputs 0, indicating that a zero-pulse step "Z" is needed to decrease the output voltage and minimize the deviation from the target voltage ratio. The output y from comparator 486 is connected to the input of multiplier 488 and is also fed back to the input of adder, thus establishing closed-loop control.

[0111] In addition, such as Figure 12 As shown, the full-pulse step “F” offers two options: a positive full-pulse step “10” and a negative full-pulse step “01”. The choice between these two full-pulse steps must be consistent with the direction of the inverter 420’s output current.

[0112] Therefore, the drive trigger command C is connected to the 488 input of the multiplier. If the 488 output of the multiplier is 1, a positive full-pulse step "10" is selected, activating inverter switches S1 and S4 (while simultaneously disabling switches S2 and S3). If the output is -1, a negative full-pulse step "01" is selected, activating switches S2 and S3 (while simultaneously disabling switches S1 and S4). Output ratio The ratio of the fundamental frequency component to the maximum output voltage of inverter 420 can be defined as the following formula.

[0113] Among them, u in It is the fundamental frequency component of the inverter output voltage, and V 直流 It is DC voltage.

[0114] According to the FAPSM principle, the output ratio It can also be defined as follows:

[0116] Where, N F and N Z These are the number of full-pulse steps "F" and zero-pulse steps "Z", respectively.

[0117] It should be noted that the states "00" and "11" of the zero-pulse ladder "Z" are redundant. Choosing either state will not affect the output waveform, regardless of the direction of current change. However, the choice of the zero-pulse ladder "Z" may affect the power loss of inverter 420. When the output of multiplier 488 is not both zero in two adjacent cycles, i.e., when the two adjacent cycles are (1, 0), (0, 1), (-1, 0), or (0, -1), system 400 alternates between the zero-pulse states "00" and "11" to prevent any switch of inverter 420 from being continuously activated, thereby balancing the power loss between switches.

[0118] If the output of multiplier 488 is zero in two adjacent cycles, the zero-pulse ladder state remains unchanged during these cycles to minimize the switching losses of inverter 420.

[0119] Furthermore, it is important to emphasize that, unlike traditional fixed-frequency voltage modulation methods (such as pulse width modulation (PWM) and pulse density modulation (PDM)), the proposed FAPSM 480 features a variable pulse frequency. This adaptability allows the 400 system to effectively compensate for resonant frequency detuning caused by variations in compensation parameters, load changes, and coupling coefficient fluctuations. In addition, the voltage and current of the inverter 420 are always in phase, ensuring ZPA operation. Notably, the FAPSM 480 exhibits a more uniform pulse distribution, which helps reduce current harmonics.

[0120] It should be noted that due to the lack of current during startup, the drive trigger command C required for the FAPSM 480 of the wireless ultrasonic motor system 400 may not be effectively generated. Therefore, during the startup phase, the system 400 should initially be configured to operate at the resonant frequency of the wireless ultrasonic motor 410. This method generates a fixed-frequency drive signal, thereby achieving stable current generation. Once a stable current is established, the system 400 can switch to the FAPSM scheme. This method combines the drive trigger command C from autonomous frequency adaptive control with the FAPSM 480, achieving a coordinated frequency modulation strategy that effectively adjusts the inverter's output voltage and frequency.

[0121] Figure 14 The FASAM scheme is shown in = 0.2 and The waveform when = 0.8. It can be observed that within five and a half cycles, = 0.2 and The number of full-pulse steps with = 0.8 are 1 and 4 respectively, which is consistent with (4). In addition, unlike the traditional PDM modulation, the positive and negative pulse distribution of the FAPSM scheme is more even and uniform, which is beneficial to reducing current harmonics and oscillations.

[0122] Figure 15 The output voltage and current of the A-phase inverter during the startup process of the wireless ultrasonic motor 410 are shown. During the initial startup phase, the inverter frequency can be set to the rated drive frequency of the wireless ultrasonic motor 410. Here, we set it to a fixed frequency of 40 kHz, and after a stable current is generated, the system switches to FAPSM mode operation. As can be seen from the magnified view, at the fixed frequency of 40 kHz, the voltage and current are out of phase, with the current slightly lagging behind the voltage. However, when operating under the FAPSM mode, the magnified view shows that the voltage and current are in phase, and the inverter switching frequency automatically adjusts to 39.771 kHz. This effectively verifies the feasibility of the proposed wireless ultrasonic motor 410 startup scheme.

[0123] Figure 16A and Figure 16B This demonstrates the FASAM scheme's ability to seamlessly regulate inverter output voltage and current. Specifically, Figure 16A and Figure 16B They are shown respectively in =1 and The output voltage and current of phase A inverter are shown when the phase ratio is 0.7. It can be seen that under both control commands, the voltage and current are in phase. Therefore, it is proven that the proposed FAPSM scheme can... Frequency adaptation is achieved for any value. Furthermore, in When =1, the RMS value of the inverter output current is 3.526 A, while When the inverter output current is 0.7, the RMS value is 2.468 A. The RMS value is 0.7 times that when =1. Therefore, the ability to regulate the inverter output voltage and current based on autonomous frequency adaptive pulse step modulation is effectively demonstrated. This effectively proves that the proposed FAPSM scheme can steplessly regulate the inverter output voltage and current.

[0124] Figure 17 It shows that for =0.6, the output voltage and current of the A-phase inverter when the equivalent capacitance of the wireless ultrasonic motor 410 changes due to factors such as running time, load, and temperature. It can be seen that the voltage and current are in phase, and the system frequency is 39.472 kHz, which is consistent with... Figure 16B Compared to other methods, this approach achieves frequency self-adaptation. Therefore, the proposed FAPSM scheme can achieve autonomous optimal frequency adjustment to overcome resonant frequency drift caused by variations in temperature, load, and operating time of the wireless ultrasonic motor. Simultaneously, the pulse ladder also achieves autonomous frequency self-adaptation to ensure that current and voltage remain in phase.

[0125] In summary, this paper presents a highly integrated wireless ultrasonic motor system 400 with autonomous frequency adaptive pulse step modulation. The system 400 includes several key components. First, it includes a dual-coil configuration characterized by vertically stacked coils designed as an IMD to enhance power transmission efficiency while minimizing magnetic coupling between the coils. It is important to note that the two coils of the IMD are not limited to circular shapes, but can also be other shapes such as square.

[0126] Furthermore, system 400 is characterized by a simplified receiver, eliminating the need for external compensation components. This design utilizes the inherent capacitive characteristics of the wireless ultrasonic motor 410 to achieve resonance with the receiving coils 440 and 440', thereby improving integration and performance.

[0127] In addition to its hardware configuration, the 400 system also includes an autonomous optimal frequency adaptive control mechanism. This mechanism adjusts the drive frequency of the wireless ultrasonic motor 410 in real time based on the changes in the equivalent impedance of the motor due to load variations, temperature fluctuations, and operating time. It uses zero-crossing detection of the inverter output current to generate corresponding drive trigger commands, thereby triggering the inverter to operate.

[0128] Furthermore, system 400 employs a frequency-adaptive pulse step modulation method. This method allows for continuous and flexible adjustment of the inverter output voltage by dynamically adjusting the pulse step amplitude and frequency, thereby generating stepless voltage control of the wireless ultrasonic motor 410.

[0129] Regarding the control details, zero-crossing detection is achieved by sampling the inverter output current. The sampled current is then processed by a zero-crossing comparator 474, which outputs a trigger command C indicating when the inverter output current crosses zero, thereby promoting phase alignment between the inverter output voltage and current.

[0130] Frequency adaptive pulse step modulation is achieved through... Modulator 481 performs the operation of processing a given target voltage ratio. This process generates command values ​​for the drive signal generation. This ensures responsiveness to varying operational requirements. The control system then integrates the drive trigger command C from the autonomous frequency adaptive control with a pulse-step modulation signal. This integration ensures frequency-adaptive pulse-step modulation of the wireless ultrasonic motor 410 at different drive frequencies, while maintaining in-phase inverter output voltage and current.

[0131] The method for initiating the operation of the wireless ultrasonic motor 410 involves a specific sequence. The operation begins by initiating operation at the rated drive frequency of the wireless ultrasonic motor 410 to establish a stable current. After this stabilization, the system 400 transitions to frequency-adaptive pulse-step modulation to dynamically adjust the drive frequency and voltage based on real-time feedback of the inverter output current, according to the state of the wireless ultrasonic motor 410.

[0132] The system is characterized by its operational capabilities. Specifically, the wireless ultrasonic motor can operate on batteries without physical connectors, reducing electrical hazards and improving safety in sensitive environments. The system's compact integration allows for enhanced mobility and flexibility in environments where traditional wiring is impractical or hazardous, such as robotic arms. In enclosed environments such as underground pipes or underwater propulsion systems, the complexities associated with installing cables through holes are avoided, preventing potential gas or liquid leaks.

[0133] Finally, the system is adaptable in its design. The dual-coil configuration can be adapted to various shapes and sizes to meet different application requirements while maintaining magnetic decoupling characteristics. Similarly, the compensation topology at the transmitter is not limited to series compensation of inductors and capacitors, but can be adapted to any other compensation structure capable of generating a high-frequency magnetic field in the transmitting coil.

[0134] The highly integrated wireless ultrasonic motor system with autonomous frequency adaptive pulse step modulation is suitable for a variety of applications, including but not limited to:

[0135] Robotics: Providing flexible and efficient power solutions for robot joints, actuators, and other components that require mobility and precision.

[0136] Medical devices: Enables wireless control in surgical instruments, prostheses, and other medical devices where reliability and safety are critical.

[0137] Consumer electronics: Powering devices that require compact design and reduced wiring complexity, such as hand tools, drones, and portable devices.

[0138] Automotive applications: Wireless power solutions that support electric vehicles and autonomous driving systems, enhancing the convenience of charging and control.

[0139] Completely enclosed environments, such as underground pipelines or underwater thrusters: This system avoids the complexity of installing cables through holes, thus preventing potential gas or liquid leaks.

[0140] Furthermore, frequency-adaptive pulse step modulation enables precise control of the drive frequency and voltage of the wireless ultrasonic motor. By continuously adjusting the pulse step, the system can quickly respond to changes in operational requirements. This feature is crucial for the aforementioned applications requiring precise control.

[0141] The embodiments described herein are presented for illustrative purposes and are not intended to be limiting. It should be understood that this application is not limited to the specific embodiments disclosed, but rather that considerable modifications, rearrangements, and combinations can be made without departing from the spirit and scope of the claims.

[0142] Unless otherwise stated or logically impermissible, any feature or element described as part of an embodiment may be combined with or substituted for any feature or element of another embodiment. Description of embodiments by way of specific features or advantages should not be construed as limiting the claims to that feature or advantage. Those skilled in the art will recognize that certain trade-offs may be made to achieve optimal system performance in a particular application, and embodiments lacking specifically described advantages may still be within the scope of the claims.

Claims

1. A drive control circuit for a wireless ultrasonic motor, the drive control circuit comprising: A high-frequency inverter configured to receive DC power and convert the DC power into high-frequency AC power; as well as At least one power conversion stage, the at least one power conversion stage comprising: A transmitter electrically connected to the high-frequency inverter, the transmitter including a transmitting coil and a compensation unit electrically connected between the high-frequency inverter and the transmitting coil, wherein the transmitter is configured to cause the transmitting coil to generate a high-frequency magnetic field in response to the high-frequency AC power; and A receiver, the receiver including a receiving coil electrically connected to the stator of the ultrasonic motor; In response to the high-frequency magnetic field generated by the transmitting coil, the receiving coil is configured to resonate with the stator, thereby generating a high-frequency AC voltage on the stator.

2. The drive control circuit as claimed in claim 1, further comprising an inductor connected in series with the receiving coil and / or a capacitor connected in parallel with the ultrasonic motor.

3. In the drive control circuit as described in claim 1, the receiving coil of the receiver is directly electrically connected to the stator of the ultrasonic motor.

4. The drive control circuit of claim 1, further comprising an additional power conversion stage independent of the at least one power conversion stage, wherein, The additional power conversion stage and the at least one power conversion stage have the same topology, including: An additional transmitter electrically connected to the high-frequency inverter, the additional transmitter including an additional transmitting coil and an additional compensation unit electrically connected between the high-frequency inverter and the additional transmitting coil, wherein the additional transmitter is configured to generate a high-frequency magnetic field in response to the high-frequency AC power; and An additional receiver, comprising an additional receiving coil directly electrically connected to the stator of the ultrasonic motor.

5. The drive control circuit as described in claim 4, wherein, The transmitting coil and the additional transmitting coil are stacked vertically to form a dual-coil structure, and the receiving coil and the additional receiving coil are stacked vertically to form an additional dual-coil structure.

6. The drive control circuit as described in claim 1 or 4, wherein: The compensation unit includes a compensation capacitor connected in series with the transmitting coil to form a series resonant circuit to provide resonance compensation.

7. The drive control circuit as described in claim 4, wherein, The drive voltage applied by the high-frequency inverter to the at least one power conversion stage maintains a 90-degree phase difference with the drive voltage applied by the high-frequency inverter to the additional power conversion stage.

8. The drive control circuit as described in claim 1, further comprising an autonomous optimal frequency adaptive control unit, wherein the autonomous optimal frequency adaptive control unit is configured to: Detecting the zero-crossing point of the output current of the high-frequency inverter; and Based on the detection of the zero-crossing point, a drive trigger command is generated, thereby triggering the high-frequency inverter to adaptively adjust its frequency so as to operate autonomously at the optimal drive frequency of the ultrasonic motor by keeping the output voltage and output current of the high-frequency inverter basically in phase.

9. The drive control circuit as described in claim 8, wherein, The autonomous optimal frequency adaptive control unit includes: A current sensor, which is electrically connected to the output of the high-frequency inverter and configured to sample the output current of the high-frequency inverter; A zero-crossing comparator, which is communicatively coupled to the current sensor and configured to output the trigger command when a zero-crossing point of the sampled output current is detected.

10. The drive control circuit of claim 8, further comprising a frequency adaptive pulse step modulation unit, the frequency adaptive pulse step modulation unit being configured to dynamically adjust the pulse step amplitude and frequency of the output voltage of the high-frequency inverter, thereby providing stepless voltage control for the motor.

11. The drive control circuit as described in claim 10, wherein, The frequency adaptive pulse step modulation unit includes: modulator, the The modulator is configured to generate a pulse step modulation signal that indicates whether a full-pulse step or a zero-pulse step is required, based on the target voltage ratio; and A multiplier, the multiplier being configured to receive from the The pulse step modulation signal from the modulator and the trigger command from the autonomous optimal frequency adaptive control unit are used to determine the switching mode of the high-frequency inverter.

12. The drive control circuit as described in claim 11, wherein, The The modulator includes: An adder configured to calculate the difference between the target voltage ratio and the comparator output; An integrator configured to integrate the output of the adder to produce an integral output; and The comparator is configured to: If the integral output exceeds 1, then an output signal indicating the full-pulse ladder is generated; or If the integral output is less than 1, then a signal indicating the zero-pulse step is output. The comparator output is fed back to the adder input, thereby forming a closed-loop control for voltage regulation.

13. A wireless ultrasonic motor drive control system, comprising: Ultrasonic motor; A high-frequency inverter configured to convert DC power into high-frequency AC power; A first wireless power transmission channel electrically connected to the high-frequency inverter, the first wireless power transmission channel including a first transmitting coil electrically connected to the high-frequency inverter via a first compensation unit and a first receiving coil electrically connected to the stator of the motor, wherein the first transmitting coil is configured to generate a first high-frequency magnetic field in response to the high-frequency AC power, and A second wireless power transmission channel, electrically connected to the high-frequency inverter and independent of the first wireless power transmission channel, includes a second transmitting coil electrically connected to the high-frequency inverter via a second compensation unit and a second receiving coil electrically connected to the stator. The second transmitting coil is configured to generate a second high-frequency magnetic field in response to the high-frequency AC power. In response to the first high-frequency magnetic field generated by the first transmitting coil and the second high-frequency magnetic field generated by the second transmitting coil, the first receiving coil and the second receiving coil are configured to resonate with the stator, thereby generating a high-frequency AC voltage on the stator. An autonomous optimal frequency adaptive control unit is configured to detect the zero-crossing point of the output current of the high-frequency inverter and, based on the detection of the zero-crossing point, generate a drive trigger command to trigger the high-frequency inverter to adaptively adjust its frequency so as to operate autonomously at the optimal drive frequency of the ultrasonic motor by keeping the output voltage and the output current of the high-frequency inverter substantially in phase.

14. The wireless ultrasonic motor drive control system as described in claim 13, wherein, The autonomous optimal frequency adaptive control unit includes: A current sensor, which is electrically connected to the output of the high-frequency inverter and configured to sample the output current of the high-frequency inverter; A zero-crossing comparator, which is communicatively coupled to the current sensor and configured to output the trigger command when a zero-crossing point of the sampled output current is detected.

15. The wireless ultrasonic motor drive control system of claim 13, further comprising a frequency adaptive pulse step modulation unit, the frequency adaptive pulse step modulation unit being configured to dynamically adjust the pulse step amplitude and frequency of the output voltage of the high-frequency inverter, thereby providing stepless voltage control for the motor.

16. The wireless ultrasonic motor drive control system as described in claim 15, wherein, The frequency adaptive pulse step modulation unit includes: modulator, the The modulator is configured to generate a pulse step modulation signal that indicates whether a full-pulse step or a zero-pulse step is required, based on the target voltage ratio; and A multiplier, the multiplier being configured to receive from the The pulse step modulation signal from the modulator and the trigger command from the autonomous optimal frequency adaptive control unit are used to determine the switching mode of the high-frequency inverter.

17. The wireless ultrasonic motor drive control system as described in claim 16, wherein, The The modulator includes: An adder configured to calculate the difference between the target voltage ratio and the comparator output; An integrator configured to integrate the output of the adder to produce an integral output; and The comparator is configured to: If the integral output exceeds 1, then an output signal indicating the full-pulse ladder is generated; or If the integral output is less than 1, then a signal indicating the zero-pulse step is output. The comparator output is fed back to the adder input, thereby forming a closed-loop control for voltage regulation.

18. The wireless ultrasonic motor drive control system as described in claim 13, wherein: The first compensation unit includes a first compensation capacitor, which is connected in series with the first transmitting coil to form a first series resonant circuit; and the second compensation unit includes a second compensation capacitor, which is connected in series with the second transmitting coil to form a second series resonant circuit. and The driving voltage applied to the first wireless power transmission channel by the high-frequency inverter maintains a 90-degree phase difference with the driving voltage applied to the second wireless power transmission channel by the high-frequency inverter.

19. A method for operating a wireless ultrasonic motor drive control system, the wireless ultrasonic motor drive control system having the structure of any one of claims 13-18, the method comprising: (a) Drive the ultrasonic motor at a fixed rated drive frequency to establish a stable inverter output current; (b) After the stable current is reached, the driving frequency of the ultrasonic motor is dynamically adjusted based on the real-time feedback of the inverter output current, and the output voltage of the high-frequency inverter is modulated using coordinated variable frequency pulse step modulation to maintain phase alignment between the output voltage and the current, thereby transitioning to a frequency adaptive pulse step modulation scheme.

20. The method of claim 19, wherein, Driving the ultrasonic motor at the fixed rated drive frequency includes setting the fixed rated drive frequency to match the resonant frequency of the ultrasonic motor during startup, so as to generate a stable drive trigger command for initial current generation before transitioning to the frequency adaptive pulse step modulation scheme.

21. The method of claim 19, wherein, The frequency-adaptive pulse step modulation scheme includes uniformly distributing positive and negative voltage pulses over multiple half-cycles to reduce current harmonics and oscillations.

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