Detailed Description
In order to make the technical solutions of the present invention better understood, the present invention will be described in further detail with reference to the accompanying drawings and specific embodiments. Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the accompanying drawings are illustrative only for the purpose of explaining the present invention, and are not to be construed as limiting the present invention. As used herein, the singular forms "a", "an", "the" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. It will be understood that when an element is referred to as being "connected" or "coupled" to another element, it can be directly connected or coupled to the other element or intervening elements may also be present. Further, "connected" or "coupled" as used herein may include wirelessly connected or coupled. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items. It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the prior art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
The embodiment of the invention provides a piezoelectric semi-active control device based on a flyback transformer, which comprises:
the main components of the device comprise: the device comprises a piezoelectric element, a vibration semi-active control circuit and a switch control signal generation module.
The piezoelectric element is adhered to the controlled structure and connected with the vibration semi-active control circuit for controlling the vibration of the structure.
The semi-active control circuit of vibration is used for controlling the voltage amplitude and the phase place at two ends of the piezoelectric element, and the semi-active control circuit of vibration includes: the device comprises a flyback transformer, a direct current voltage source, three analog electronic switches and at least two diodes.
The switch control signal generation module consists of a microcontroller and an analog switch driving module (also called as a driving circuit).
The direct-current voltage source is used for inputting electric energy to the primary side of the flyback transformer, the flyback transformer is used for inputting electric energy to the piezoelectric element, and the time sequence of the input electric energy is controlled by the analog electronic switch. The piezoelectric semi-active control system based on the flyback transformer shown in fig. 1 comprises a piezoelectric element, a vibration semi-active control circuit and a switch control signal generation module. The piezoelectric element is attached to the cantilever beam and connected with the vibration semi-active control circuit to serve as a driver to control vibration of the structure. The vibration semi-active control circuit is a circuit for realizing the SSDEI technology and comprises an analog electronic switch, a flyback transformer with high quality factor, two diode modules and a direct-current voltage source.
In this embodiment, the analog electronic switch may include a voltage-reversal control switch group and an energy-injection control switch. The switch control signal generation module comprises a control signal feedback module, a microcontroller and an analog switch driving module, wherein the control signal feedback module is connected with the microcontroller, and the microcontroller is connected with the analog switch driving module. Specifically, each analog electronic switch includes: a voltage reversal control switch group and an energy injection control switch. Wherein, voltage upset control switch group includes: the first N-channel MOS tube and the P-channel MOS tube are used for controlling the vibration semi-active control circuit to work so as to realize the voltage overturning action of the piezoelectric element.
The energy injection control switch includes: and the second N-channel MOS tube is used for adjusting the electric energy injected into the flyback transformer.
In this embodiment, the flyback transformer further includes: the primary winding comprises a first secondary winding, a second secondary winding and a primary winding, wherein the same-name ends of the first secondary winding and the second secondary winding are the same and are opposite to the primary winding, and the turn ratio of the three windings can be any value in principle. And the primary coil is used for converting the electric energy of the direct-current power supply into magnetic field energy and storing the magnetic field energy into the flyback transformer. The first secondary side coil and the second secondary side coil are used for converting magnetic field energy into electric energy and injecting the electric energy into the piezoelectric element in the voltage overturning process so as to improve the amplitude of overturning voltage.
In this embodiment, the switch control signal generation module further includes a control signal feedback module. And the control signal feedback module is used for acquiring the vibration displacement of the controlled structure in real time. And the microcontroller is used for processing the control logic and generating a switch control signal. And the analog switch driving module is used for driving the corresponding electronic switch to be switched on or switched off according to the control signal output by the microcontroller.
In this embodiment, the vibration semi-active control circuit is specifically a piezoelectric semi-active control circuit based on a flyback transformer, and mainly includes: the energy injection circuit comprises a voltage reversal circuit and an energy injection circuit.
Wherein, the voltage reversal circuit includes:
the first N-channel MOS tube, the P-channel MOS tube, the first rectifier diode, the second rectifier diode and the first secondary side coil and the second secondary side coil of the flyback transformer. The anode of the first rectifier diode is connected with one surface of the piezoelectric element, and the cathode of the first rectifier diode is connected with the dotted terminal of the first secondary coil of the flyback transformer. The drain electrode of the first N-channel MOS tube is connected with the non-dotted terminal of the first secondary coil of the flyback transformer, the source electrode of the first N-channel MOS tube is connected with the other surface of the piezoelectric element and grounded, and the grid electrode of the first N-channel MOS tube is connected with the analog switch driving module. And the cathode of the second rectifier diode is connected with one end of the piezoelectric element, and the anode of the second rectifier diode is connected with the non-dotted end of the second secondary coil of the flyback transformer. The drain electrode of the P-channel MOS tube is connected with the dotted terminal of the second secondary coil of the flyback transformer, the source electrode of the P-channel MOS tube is connected with the other end of the piezoelectric element and grounded, and the grid electrode of the P-channel MOS tube is connected with the analog switch driving module.
The energy injection circuit comprises: the second N-channel MOS tube, a primary coil of the flyback transformer and a direct current voltage source. The drain electrode of the second N-channel MOS tube is connected with the negative electrode of the direct-current voltage source, the source electrode of the second N-channel MOS tube is connected with the non-dotted terminal of the flyback transformer and grounded, and the grid electrode of the second N-channel MOS tube is connected with the analog switch driving module. And the positive electrode of the direct-current voltage source is connected with the dotted terminal of the primary coil of the flyback transformer.
In this embodiment, the diode of the vibration semi-active control circuit includes: the diode of the vibration semi-active control circuit is used for automatically ending voltage overturning action after voltage overturning.
In this embodiment, an operation process of the piezoelectric semi-active control device may be designed, which at least includes the following steps:
and a displacement signal of the structural vibration is obtained in real time through a control signal feedback module and is transmitted to the microcontroller.
The microcontroller detects the extreme value of the displacement signal in real time and generates two switch signals at the extreme value to be transmitted to the analog switch driving module.
The analog switch driving module amplifies the two switch signals and outputs a switch driving analog signal 1 and a switch driving analog signal 2 which respectively act on the voltage turnover control switch group and the energy injection control switch.
The energy injection control switch controls the energy injection loop to work and adjusts the electric energy injected into the flyback transformer before the action of turning over the voltage starts under the action of the switch driving analog signal 2.
The flyback transformer converts the injected electric energy into magnetic field energy to be stored and converts the magnetic field energy into electric energy to be injected into a voltage overturning loop of the vibration control semi-active control circuit when the voltage overturning action starts.
The voltage overturning control switch group controls the voltage overturning loop to work under the drive of the switch driving analog signal 1 to realize the voltage overturning action of the piezoelectric element, and the diode automatically finishes the action of voltage overturning after the voltage overturning.
The design objectives of the present invention are: the piezoelectric semi-active control circuit and method based on the flyback transformer are simple in structure and easy to achieve. Compared with the SSDV technology, the vibration control method can achieve better vibration control effect under the condition of using an external voltage source with the same voltage; furthermore, compared with a more complex self-adaptive voltage source regulating circuit in the improved SSDV technology, the method can realize the self-adaptive regulation of the output voltage along with the structural vibration displacement only by self-adaptively regulating the switching signal generated by the microcontroller, thereby improving the robustness of the system.
The general design idea lies in that: on the basis of the SSD technology, a Synchronous Switch Damping (SSDEI) control method based on energy injection is provided. The piezoelectric element is adhered to the controlled structure and connected with the vibration semi-active control circuit to be used as the vibration of the driver control structure. The vibration semi-active control circuit comprises an analog electronic switch and a flyback transformer with high quality factor, and is respectively used for controlling the on-off of the vibration semi-active control circuit and the electric energy conversion of the primary side and the secondary side. The analog electronic switch comprises a voltage reversal control switch group and an energy injection control switch. The switch control signal generation module is used for generating a switch driving analog signal 1 and a switch driving analog signal 2 and respectively acting on the voltage turnover control switch group and the energy injection control switch. The switch driving analog signal 2 controls the energy injection control switch to adjust the electric energy injected into the flyback transformer, and the switch driving analog signal 1 controls the voltage turnover control switch group to change the amplitude and the phase of the voltage at two ends of the piezoelectric element, so that the energy of electromechanical conversion is improved to realize the optimal control function of structural vibration.
Compared with the existing SSDV technology, the vibration control circuit can achieve a better vibration control effect under the condition that an external voltage source with the same voltage is used, and compared with the improved SSDV technology, the vibration control circuit has the problems that a direct-current voltage source circuit is complex in structure and cannot share the ground with a control circuit, and the like.
The following will illustrate the practical application of this embodiment with reference to specific examples:
as shown in figure 1, a sinusoidal exciting force with the same frequency as the first-order resonance frequency of the cantilever beam is generated by the exciter and acts on one end of the cantilever beam to enable the cantilever beam to resonate. The piezoelectric element is attached to the cantilever beam and vibrates with the same frequency and the same phase as the cantilever beam to generate an alternating voltage signal, the laser displacement sensor is used as a control signal feedback module to measure the vibration displacement of the other end of the cantilever beam and generate a sinusoidal displacement analog signal, and the alternating voltage signal generated by the piezoelectric element is in the same phase with the sinusoidal displacement signal measured by the laser displacement sensor when the cantilever beam resonates at the first-order resonant frequency.
The microcontroller converts the displacement analog signal output by the laser displacement sensor into a digital signal, detects the extreme value of the displacement digital signal in real time through a control logic program, respectively generates a switch digital signal 1 and a switch digital signal 2 at the extreme value, and generates a switch driving analog signal 1 and a switch driving analog signal 2 through the amplification of the analog switch driving module after converting the displacement analog signal into the analog signal and respectively acts on the voltage turnover control switch group and the energy injection control switch;
as shown in fig. 2, the flyback transformer in the SSDEI circuit divides the circuit into two parts, namely a voltage inversion loop and an energy injection loop. The voltage reversal circuit is composed of two secondary windings L1、L2And N-channel MOS transistor S1P-channel MOS transistor S2And two rectifier diodes D1、D2Formed and attached directly to the piezoelectric element. The energy injection loop is composed of a primary coil L3N-channel MOS transistor S3And direct currentPressure source V1And (4) forming. Switch driving analog signal 1 generated by analog switch driving module acts on N-channel MOS tube S1And P channel MOS tube S2And when the voltage of the switch driving analog signal 1 is positive S1Conducting S2When the power is off and the voltage is negative S2Conducting S1Disconnecting; switch driving analog signal 2 acts on N-channel MOS tube S3On the gate of (1), and S3Only conduct when the switch driving analog signal 2 voltage is positive and reaches a threshold.
As shown in fig. 3 and 4, the SSDEI circuit performs two actions in one vibration cycle of the cantilever, which are respectively turning the voltage of the piezoelectric element from positive to negative and from negative to positive, and continuously repeats the two actions in other vibration cycles of the cantilever. The operation of the SSDEI circuit in which the voltage of the piezoelectric element is inverted from positive to negative in one operation cycle of the SSDEI circuit is arbitrarily taken, and the operation principle of the SSDEI circuit is further described with reference to fig. 3 and 4 (in the operation process, the voltages of the switch driving analog signal 1 and the switch driving analog signal 2 both reach the conduction threshold voltage of the MOS transistor):
(1) in the time period, the voltage of the switch driving analog signal 1 is negative, and the voltage of the switch driving analog signal 2 is zero, so that the P-channel MOS transistor S2Conducting N-channel MOS transistor S3And (5) disconnecting. Since the voltage across the piezoelectric element is now positive, the rectifier diode D is thus present2In a reverse cut-off state, so that the circuit is always kept in an open state in the period;
(2) in the period, the voltage of the switch driving analog signal 1 is still negative, and the voltage of the switch driving analog signal 2 is changed into positive, so that the P-channel MOS transistor S2And N-channel MOS transistor S3Are all in a conducting state. At this time, the voltage on the piezoelectric element is still positive and the dotted terminal of the flyback transformer is reversed to cause the secondary coil L2Voltage direction and zener diode D2Opposite polarity, so that the rectifier diode D2Still in the reverse blocking state, i.e. the left circuit part is still in the open state. At this time, the primary coil L3And a DC voltage source V1Forming a closed loop, DC voltage source V1By passing throughSide coil L3And charging the flyback transformer. Primary coil L in this period3The direction and the variation curve of the working current are shown as I in fig. 3 and 4priShown;
(3) the moment the voltage of the switching signal 2 changes to be negative in the period, the voltage of the switching signal 1 changes to be positive, namely the N-channel MOS tube S3Disconnected instant N-channel MOS tube S1And conducting. At this time, the secondary coil L1Piezoelectric element, rectifier diode D1A closed loop is formed, the circuit is similar to an LC oscillating circuit due to the capacitance of the piezoelectric element, a high-frequency oscillating loop is formed, and the voltage of the piezoelectric element and the N-channel MOS tube S are enabled to pass through a half oscillation period1Reverse before conduction, at which time the rectifier diode D1The reverse cutoff opens the LC tank. And in the last step, the flyback transformer passes through the primary coil L3The stored energy passes through the secondary winding L when the voltage is reversed1Injection into the tank circuit further increases the amplitude of the voltage across the piezoelectric element. Secondary winding L in this period1The working current direction and curve are shown as I in fig. 3 and 4secAs shown.
The operation of the SSDEI circuit to reverse the voltage of the piezoelectric element from negative to positive is the same as the operation of reversing the voltage from positive to negative in principle, and is only due to the secondary winding L of the flyback transformer2And a rectifier diode D2Direction of connection in oscillating circuit with secondary winding L1And a rectifier diode D1The direction in the tank circuit is reversed and the voltage of the piezoelectric element before reversal is negative, so that the reversed voltage direction is reversed.
The two actions not only enable the force generated by the piezoelectric element to keep opposite to the structural speed, but also increase the amplitude of the voltage on the piezoelectric element, thereby improving the electromechanical conversion efficiency, improving the electromechanical conversion energy of the system and playing the role of vibration control.
Furthermore, the microcontroller adaptively adjusts the duty ratio of the switch driving analog signal 2 according to the vibration displacement amplitude of the cantilever beam, so that the direct-current voltage source can be adaptively adjusted to the primary side coil when the right part loop of the SSDEI circuit worksL3The magnitude of the charged energy, namely the magnitude of the energy injected into the oscillating circuit by the flyback transformer during voltage overturning, thereby realizing the self-adaptive adjustment of the magnitude of the voltage amplification when the SSDEI circuit overturns the voltage of the piezoelectric element according to the change of the vibration amplitude of the cantilever beam. When the cantilever beam vibrates in a small amplitude, if the voltage with overlarge amplification is over-large, the cantilever beam is unstable, and new vibration is generated, so that the robustness of the vibration control system can be improved by adaptively adjusting the voltage amplification according to the vibration amplitude of the vibration structure.
Compared with the SSDV technology, the vibration control circuit can achieve a better vibration control effect under the condition that an external voltage source with the same voltage is used, and compared with the improved SSDV technology, the vibration control circuit has the problems that a direct-current voltage source circuit is complex in structure and cannot be grounded with a control circuit, and the like.
The embodiments in the present specification are described in a progressive manner, and the same and similar parts among the embodiments are referred to each other, and each embodiment focuses on the differences from the other embodiments. In particular, for the apparatus embodiment, since it is substantially similar to the method embodiment, it is relatively simple to describe, and reference may be made to some descriptions of the method embodiment for relevant points. The above description is only for the specific embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.