Rectification interface circuit for piezoelectric vibration energy acquisition

Abstract

The invention discloses a rectification interface circuit for piezoelectric vibration energy collection, and the circuit comprises a piezoelectric transducer which is connected with the two ends of a switch and energy storage module; the switch is connected with the energy storage module and two ends of the inductor, and the voltage output end is connected with a to-be-powered load; the first input end and the third input end of the detection and control module are connected with one end of the piezoelectric transducer, the second input end and the fourth input end of the detection and control module are connected with the other end of the piezoelectric transducer, the fifth input end of the detection and control module is connected with the voltage output end of the switch and energy storage module, and the sixth input end of the detection and control module is connected with one end of the inductor; the output end is connected with the input end of the switch and energy storage module; the detection and control module is used for cooperatively controlling the working state of each switching tube in the switch and energy storage module and the charging state of the inductor, so that the voltage of the piezoelectric transducer is overturned, and the equivalent impedance of the piezoelectric transducer is matched with the equivalent load impedance of the switch and energy storage module; in this way, the output voltage of the piezoelectric transducer is maintained at the maximum power point voltage level.

Description

Technical Field

[0001] The present invention belongs to the technical field of micro energy collection, and in particular relates to a rectifier interface circuit for collecting piezoelectric vibration energy. Background Art

[0002] With the continued development of IoT devices and low-power smart sensors, achieving long-term stable power supply has become a key challenge in system design. Piezoelectric energy harvesting technology has become a key candidate for edge power supply due to its battery-free and sustainable operation.

[0003] Piezoelectric vibration energy harvesting technology utilizes the piezoelectric effect of piezoelectric materials to convert mechanical vibrations in the environment into electrical energy. Currently, existing piezoelectric vibration energy harvesting technologies mainly include full-bridge rectifier structure, synchronous switching inductor technology, and synchronous charge extraction technology. However, the existing full-bridge rectifier has a simple structure and can only collect energy when the piezoelectric voltage of the piezoelectric transducer is higher than the output voltage, that is, it cannot extract energy when the piezoelectric voltage is lower than the output voltage. Therefore, part of the electrical energy will be wasted, resulting in low piezoelectric energy harvesting efficiency. In addition, the existing synchronous switching inductor technology and synchronous charge extraction technology mainly rely on large inductance and high-power control circuits, which will increase the system volume and cost, and perform poorly in strong electromechanical coupling scenarios, and the energy extraction efficiency is significantly reduced.

[0004] Therefore, how to improve the energy collection efficiency of piezoelectric transducers is a technical problem that needs to be solved urgently. Summary of the Invention

[0005] To improve the energy harvesting efficiency of piezoelectric transducers, the present invention provides a rectifier interface circuit for harvesting piezoelectric vibration energy. The technical problem to be solved by the present invention is achieved through the following technical solutions: The present invention provides a rectifier interface circuit for collecting piezoelectric vibration energy, comprising: Piezoelectric transducers, switches and energy storage modules, inductors, and detection and control modules; a piezoelectric transducer connected to both ends of the switch and the energy storage module; The switch and energy storage module are connected to both ends of the inductor, and the voltage output end is connected to the load to be powered; A detection and control module, wherein the first input terminal and the third input terminal are connected to one end of the piezoelectric transducer, the second input terminal and the fourth input terminal are connected to the other end of the piezoelectric transducer, the fifth input terminal is connected to the voltage output terminal of the switch and energy storage module, the sixth input terminal is connected to one end of the inductor, and the output terminal is connected to the input terminal of the switch and energy storage module; the detection and control module is used to coordinately control the working state of each switch tube in the switch and energy storage module and the charging state of the inductor, so that the voltage of the piezoelectric transducer is reversed, and the equivalent impedance of the piezoelectric transducer and the inductor is matched with the equivalent load impedance of the switch and energy storage module, so as to maintain the output voltage of the piezoelectric transducer at the maximum power point voltage level.

[0006] In one embodiment of the present invention, the switch and energy storage module includes: A first switch tube, having a first end connected to the ground, a second end connected to the first end of the second switch tube and one end of the piezoelectric transducer, and a third end connected to the output terminal CK1 of the detection and control module; a second switch tube, having a second end connected to the second end of the fourth switch tube, the second end of the fifth switch tube, the second end of the seventh switch tube, and one end of the inductor, and a third end connected to the output terminal CK2 of the detection and control module; a third switch tube, having a first end connected to the ground, a second end connected to one end of the piezoelectric transducer and the first end of the fourth switch tube, and a third end connected to the output terminal CK3 of the detection and control module; A fourth switch tube, a third end of which is connected to the output terminal CK4 of the detection and control module; a fifth switch tube, having a first end connected to the first end of the sixth switch tube and one end of the energy storage element, and a third end connected to the output terminal CK5 of the detection and control module; a sixth switch tube, having a second end connected to the second end of the eighth switch tube, the second end of the ninth switch tube, and the other end of the inductor, and a third end connected to the output terminal CK6 of the detection and control module; A seventh switch tube, a first end of which is grounded, and a third end of which is connected to the output terminal CK7 of the detection and control module; An eighth switch tube, a first end of which is grounded, and a third end of which is connected to the output terminal CK8 of the detection and control module; The ninth switch tube, the first terminal and the output capacitor C OUT One end of the connection; Output capacitor C OUT , the end not connected to the ninth switch tube is grounded; The energy storage element has an end not connected to the fifth switching tube that is grounded.

[0007] In one embodiment of the present invention, the second switch tube and the fourth switch tube include: a transmission gate and an inverter; The control input end of the transmission gate is connected to the input end of the inverter, and the inverting control input end of the transmission gate is connected to the output end of the inverter; wherein, the data input end of the transmission gate is the first end of the second switch tube or the fourth switch tube, the data output end of the transmission gate is the second end of the second switch tube or the fourth switch tube, and the control input end of the transmission gate is the third end of the second switch tube or the fourth switch tube.

[0008] In one embodiment of the present invention, the detection and control module includes: A signal detection and flip control module, having a first input end connected to one end of the piezoelectric transducer, a second input end connected to the other end of the piezoelectric transducer, and an output end connected to the first input end of the output voltage regulation module; Output voltage regulation module, the second input terminal and the output capacitor C OUT The ungrounded end is connected, the third input end is connected to one end of the inductor, and the first output end, the second output end and the third output end are connected to the first input end, the second input end and the third input end of the logic control module respectively; A logic control module, wherein the first output terminal CK1 is connected to the third terminal of the first switching tube, the second output terminal CK2 is connected to the third terminal of the second switching tube, the third output terminal CK3 is connected to the third terminal of the third switching tube, the fourth output terminal CK4 is connected to the third terminal of the fourth switching tube, the fifth output terminal CK5 is connected to the third terminal of the fifth switching tube, the sixth output terminal CK6 is connected to the third terminal of the sixth switching tube, the seventh output terminal CK7 is connected to the third terminal of the seventh switching tube, the eighth output terminal CK8 is connected to the third terminal of the eighth switching tube, and the ninth output terminal CK9 is connected to the third terminal of the ninth switching tube.

[0009] In one embodiment of the present invention, the signal detection and flip control module includes: A differential voltage detection module, having a first input end connected to one end of the piezoelectric transducer, a second input end connected to the other end of the piezoelectric transducer, and an output end connected to the input end of the voltage-current conversion module; a voltage-current conversion module, an output end of which is connected to the first input end of the adaptive frequency multiplier module; A peak voltage detection module, having a first input end connected to one end of the piezoelectric transducer, a second input end connected to the other end of the piezoelectric transducer, and an output end connected to the input end of the frequency and inversion factor control module; The frequency and flip factor control module has an output terminal connected to the second input terminal of the adaptive frequency multiplier module; The adaptive frequency multiplier module has an output end connected to the first input end of the output voltage regulation module.

[0010] In one embodiment of the present invention, the output voltage regulation module includes: a constant time conduction module, wherein the input end is connected to the output end of the detection and control module, and the first output end is connected to the first input end of the logic control module; Load detection module, input and output capacitor C OUT The ungrounded end is connected, and the first output end is connected to the second input end of the logic control module; The zero-crossing detection module has a first input end connected to one end of the inductor, a second input end connected to the second output end of the constant time conduction module, a third input end connected to the second output end of the load detection module, and an output end connected to the third input end of the logic control module.

[0011] In one embodiment of the present invention, the differential voltage detection module is used to detect the voltage difference between the two ends of the piezoelectric transducer and input the voltage difference to the voltage-current conversion module; a voltage-current conversion module, configured to convert the received voltage difference into a proportional current signal, and input the proportional current signal into the adaptive frequency multiplier module; The peak voltage detection module is used to detect the positive / negative voltage peak of the piezoelectric transducer output voltage signal. When the positive / negative voltage peak is detected, a pulse signal is generated and sent to the frequency and flip factor control module, and the inherent capacitance C of the piezoelectric transducer is converted to P forming a first LC resonant circuit with the inductor, and transferring energy in the piezoelectric transducer to the inductor through the first LC resonant circuit, so that the voltage of the piezoelectric transducer begins to reverse; when the current of the inductor passes through zero, reversely transferring the energy stored in the inductor to the piezoelectric transducer through the LC resonant circuit, so that the voltage of the piezoelectric transducer stops reversing; A frequency and inversion factor control module, configured to determine the frequency and voltage inversion factor of the piezoelectric transducer based on the received pulse signal, and input the frequency and voltage inversion factor of the piezoelectric transducer into the adaptive frequency multiplier module; The adaptive frequency multiplier module is used to generate a corresponding frequency multiplication signal based on the received proportional current signal, the frequency of the piezoelectric transducer and the voltage reversal factor, and input the frequency multiplication signal to the output voltage regulation module.

[0012] In one embodiment of the present invention, the constant time conduction module is used to generate a fixed time length switch tube conduction signal T ON , to control the conduction time of the first switch tube, the second switch tube, the third switch tube, the fourth switch tube, the fifth switch tube, the sixth switch tube, the seventh switch tube, the eighth switch tube and the ninth switch tube.

[0013] In one embodiment of the present invention, the load detection module is used to detect the output capacitance C OUT The output voltage V at the ungrounded end OUT , when the output voltage VOUT When the voltage is less than the threshold, the inductor and output capacitor C OUT A second LC resonant circuit is formed, and energy is extracted from the energy storage element through the second LC resonant circuit to supply power to the load to be powered; when the output voltage V OUT When the load voltage is less than the reference voltage, the inherent capacitance C of the piezoelectric transducer is P The first LC resonant circuit is formed with the inductor. After the energy in the piezoelectric transducer is transferred to the inductor through the first LC resonant circuit, the inductor and the output capacitor C are connected. OUT A second LC resonant circuit is formed, and the energy in the inductor is transferred to the output capacitor C through the second LC resonant circuit. OUT To supply power to the load to be powered; when the output voltage V OUT When the light-load reference voltage is greater than the reference voltage, the inherent capacitance C of the piezoelectric transducer is P A first LC resonant circuit is formed with the inductor, and energy in the piezoelectric transducer is extracted through the first LC resonant circuit to the energy storage element for storage.

[0014] In one embodiment of the present invention, the zero-crossing detection module is used to detect whether the current of the inductor crosses zero, and output a shutdown signal to the logic control module when the current of the inductor crosses zero, so as to control the shutdown moments of the first switch tube, the second switch tube, the third switch tube, the fourth switch tube, the fifth switch tube, the sixth switch tube, the seventh switch tube, the eighth switch tube, and the ninth switch tube.

[0015] Compared with the prior art, the present invention has the following beneficial effects: The present invention omits the rectifier capacitor required in the traditional parallel synchronous switch inductor energy extraction architecture, that is, the energy generated by the piezoelectric transducer can be supplied to the load to be powered through a single conversion without the need for a rectifier capacitor, effectively suppressing the cascade loss common in traditional multi-stage structures, significantly improving the energy conversion efficiency, reducing the circuit area and system cost, and improving the feasibility of on-chip integration. The circuit also has the characteristics of stable output voltage and small ripple, which is conducive to improving the power supply performance to the subsequent load.

[0016] Furthermore, by collaboratively controlling the switch on-time and the inductor's charge state, the equivalent impedance of the piezoelectric transducer and inductor is matched to the equivalent load impedance of the switch and energy storage module, enabling maximum power point tracking of piezoelectric energy harvesting and improving energy conversion efficiency. Compared to traditional energy harvesting methods based on weak coupling scenarios (such as synchronous switch induction or synchronous charge extraction), this invention avoids the reliance on large inductors and complex, high-power control circuits, effectively reducing system power consumption and size.

[0017] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a structural diagram of a rectifier interface circuit for collecting piezoelectric vibration energy provided by an embodiment of the present invention; Figure 2 is a schematic diagram of an equivalent circuit of a piezoelectric transducer provided by an embodiment of the present invention; Figure 3 Schematic diagram of a circuit consisting of a piezoelectric transducer, an inductor, a switch, and an energy storage module provided by an embodiment of the present invention; Figure 4 This is a circuit structure diagram of a detection and control module provided by an embodiment of the present invention; Figure 5 is a circuit structure diagram of a differential voltage detection module provided by an embodiment of the present invention; Figure 6 This is a circuit structure diagram of a voltage-current conversion module provided by an embodiment of the present invention; Figure 7 This is a current flow diagram of a piezoelectric transducer during a voltage reversal phase provided by an embodiment of the present invention; Figure 8 1 is a schematic diagram of a circuit structure of a peak voltage detection module provided by an embodiment of the present invention; Figure 9 is a circuit structure diagram of an adaptive frequency multiplier module provided by an embodiment of the present invention; Figure 10 This is a circuit structure diagram of a constant time conduction module provided by an embodiment of the present invention; Figure 11 This is a current flow diagram for extracting energy from an energy storage element to supply power to a load, provided by an embodiment of the present invention; Figure 12 This is a current flow diagram for extracting energy from a piezoelectric transducer to power a load to be powered, provided by an embodiment of the present invention; Figure 13 This is a current flow diagram for extracting energy from a piezoelectric transducer to an energy storage element, provided by an embodiment of the present invention; Figure 14 is a circuit structure diagram of a load detection module provided by an embodiment of the present invention; Figure 15 This is a circuit structure diagram of a zero-crossing detection module provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0019] In order to further illustrate the technical means and effects adopted by the present invention to achieve the predetermined purpose of the invention, the following is a detailed description of a rectifier interface circuit for piezoelectric vibration energy collection proposed in accordance with the present invention in conjunction with the accompanying drawings and specific implementation methods.

[0020] The aforementioned and other technical contents, features, and effects of the present invention are clearly presented in the following detailed description of the specific embodiments in conjunction with the accompanying drawings. Through the description of the specific embodiments, a deeper and more specific understanding of the technical means and effects adopted by the present invention to achieve the intended purpose can be obtained. However, the accompanying drawings are provided for reference and illustration purposes only and are not intended to limit the technical solutions of the present invention.

[0021] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations are intended to cover non-exclusive inclusion, such that an article or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the article or device comprising the element.

[0022] In order to improve the energy collection efficiency of piezoelectric transducers, the present invention provides a rectifier interface circuit for piezoelectric vibration energy collection. Figure 1 As shown, the circuit includes: a piezoelectric transducer, a switch and energy storage module, an inductor, and a detection and control module. The piezoelectric transducer is connected to both ends of the switch and energy storage module; the switch and energy storage module is connected to both ends of the inductor, and the voltage output end is connected to the load to be powered; the detection and control module has a first input end and a third input end connected to one end of the piezoelectric transducer, a second input end and a fourth input end connected to the other end of the piezoelectric transducer, a fifth input end connected to the voltage output end of the switch and energy storage module, a sixth input end connected to one end of the inductor, and an output end connected to the input end of the switch and energy storage module; the detection and control module is used to coordinately control the working state of each switch tube in the switch and energy storage module and the charging state of the inductor, so as to reverse the voltage of the piezoelectric transducer and match the equivalent impedance of the piezoelectric transducer and the inductor with the equivalent load impedance of the switch and energy storage module, so as to maintain the output voltage of the piezoelectric transducer at the maximum power point voltage level.

[0023] In some examples, the equivalent circuit diagram of the piezoelectric transducer can be found in Figure 2 As shown, the equivalent circuit diagram includes the inductor current I P , inherent capacitance C P and resistor R P Inductor current I P , capacitor C P and resistor R P are connected in parallel. Among them, the capacitor C PThe two ends of the piezoelectric transducer are V P terminal and V N end.

[0024] Specifically, the switch and energy storage module includes: a first switch tube, a first end of which is grounded, a second end of which is commonly connected to the first end of the second switch tube and one end of the piezoelectric transducer, and a third end of which is connected to the output terminal CK1 of the detection and control module; a second switch tube, a second end of which is commonly connected to the second end of the fourth switch tube, the second end of the fifth switch tube, the second end of the seventh switch tube and one end of the inductor, and a third end of which is connected to the output terminal CK2 of the detection and control module; a third switch tube, a first end of which is grounded, a second end of which is commonly connected to one end of the piezoelectric transducer and the first end of the fourth switch tube, and a third end of which is connected to the output terminal CK3 of the detection and control module; a fourth switch tube, a third end of which is connected to the output terminal CK1 of the detection and control module; The first end of the fifth switch tube is connected to the first end of the sixth switch tube and one end of the energy storage element, and the third end is connected to the output terminal CK5 of the detection and control module; the second end of the sixth switch tube is connected to the second end of the eighth switch tube, the second end of the ninth switch tube and the other end of the inductor, and the third end is connected to the output terminal CK6 of the detection and control module; the first end of the seventh switch tube is grounded, and the third end is connected to the output terminal CK7 of the detection and control module; the first end of the eighth switch tube is grounded, and the third end is connected to the output terminal CK8 of the detection and control module; the first end of the ninth switch tube is connected to the output capacitor C OUT One end of the output capacitor C OUT , the end not connected to the ninth switch tube is grounded; the end of the energy storage element not connected to the fifth switch tube is grounded.

[0025] Furthermore, the second and fourth switching transistors include a transmission gate and an inverter. The control input of the transmission gate is connected to the input of the inverter, and the inverting control input of the transmission gate is connected to the output of the inverter. The data input of the transmission gate is the first terminal of the second or fourth switching transistor, the data output of the transmission gate is the second terminal of the second or fourth switching transistor, and the control input of the transmission gate is the third terminal of the second or fourth switching transistor.

[0026] For example, Figure 3 The schematic diagram of a circuit consisting of a piezoelectric transducer PZT, an inductor L, a switch, and an energy storage module. The energy storage element is the energy storage capacitor C. STO The transmission gate S2 and the inverter INV2 form the second switch tube, the transmission gate S4 and the inverter INV4 form the fourth switch tube, S1, S3, S5~S9 represent the first switch tube, the third switch tube, the fifth switch tube to the ninth switch tube, and one end V of the piezoelectric transducer PZT P The data input terminal of S2 and the second terminal (ie, drain) of S1 are connected together, and the other terminal VN The data input terminal of S4 and the second terminal (i.e., drain) of S3 are connected together. S1, S3, S7, and S8 are NMOS transistors, and S5, S6, and S9 are PMOS transistors. The third terminal (i.e., gate) of S1, the control input terminal of S2, the gate of S3, the control input terminal of S4, and the gates of S5 to S9 are all connected to the output terminals CK1 to CK9 of the detection and acquisition control module. One end of the inductor L is VSW1, and the other end is VSW2. The output capacitor C OUT The ungrounded end is connected to the source of S9, and the ungrounded end of the energy storage capacitor CSTO is connected to the sources of S5 and S6. It can be seen that in the circuit provided by the present invention, no rectifier current is designed between the inductor L and the PZT. Instead, the above-mentioned S2, INV2, S4, and INV4 are designed. This allows the energy generated by the piezoelectric transducer to be supplied to the load to be powered without the need for a rectifier capacitor, and the switch on time and the charging state of the inductor are coordinated to match the equivalent impedance of the piezoelectric transducer and inductor with the equivalent load impedance of the switch and the energy storage module, thereby achieving maximum power point tracking for piezoelectric energy collection.

[0027] Specifically, the detection and control module includes: a signal detection and inversion control module, an output voltage regulation module and a logic control module.

[0028] Among them, the first input terminal of the signal detection and flip control module is connected to the V P The second input terminal is connected to the V N The output terminal is connected to the first input terminal of the output voltage regulating module; the second input terminal of the output voltage regulating module is connected to the output capacitor C OUT The ungrounded end is connected to the third input terminal and the V SW1 The first output terminal CK1 of the logic control module is connected to the gate of the first switch tube S1, the second output terminal CK2 is connected to the control input terminal of the transmission gate S2, the third output terminal CK3 is connected to the gate of the third switch tube S3, the fourth output terminal CK4 is connected to the control input terminal of the transmission gate S4, the fifth output terminal CK5 is connected to the gate of the fifth switch tube S5, the sixth output terminal CK6 is connected to the gate of the sixth switch tube S6, the seventh output terminal CK7 is connected to the gate of the seventh switch tube S7, the eighth output terminal CK8 is connected to the gate of the eighth switch tube S8, and the ninth output terminal CK9 is connected to the gate of the ninth switch tube S9.

[0029] In some embodiments, the signal detection and inversion control module includes: a signal detection and inversion control module, an output voltage regulation module, and a logic control module.

[0030] Among them, the signal detection and flip control module, the first input end and the V P The second input terminal is connected to the V N The output terminal is connected to the first input terminal of the output voltage regulating module; the second input terminal of the output voltage regulating module is connected to the output capacitor C OUT The ungrounded end is connected to the third input terminal and the V SW1 The first output terminal, the second output terminal and the third output terminal are connected to the first input terminal T of the logic control module respectively. ON2 , the second input terminal T ON2 And the third input terminal T ON2 Connection: The first output terminal CK1 of the logic control module is connected to the gate of the first switch tube S1, the second output terminal CK2 is connected to the control input terminal of the transmission gate S2, the third output terminal CK3 is connected to the gate of the third switch tube S3, the fourth output terminal CK4 is connected to the control input terminal of the transmission gate S4, the fifth output terminal CK5 is connected to the gate of the fifth switch tube S5, the sixth output terminal CK6 is connected to the gate of the sixth switch tube S6, the seventh output terminal CK7 is connected to the gate of the seventh switch tube S7, the eighth output terminal CK8 is connected to the gate of the eighth switch tube S8, and the ninth output terminal CK9 is connected to the gate of the ninth switch tube S9.

[0031] In some examples, the signal detection and inversion control module includes: a differential voltage detection module, a voltage-current conversion module, a peak voltage detection module, a frequency and inversion factor control module, and an adaptive frequency multiplier module.

[0032] The first input terminal of the differential voltage detection module is connected to the V P The second input terminal is connected to the V N The output end of the voltage-current conversion module is connected to the input end of the voltage-current conversion module; the output end of the voltage-current conversion module is connected to the first input end of the adaptive frequency multiplier module; the first input end of the peak voltage detection module is connected to the V P The second input terminal is connected to the V N The output end of the frequency and inversion factor control module is connected to the input end of the frequency and inversion factor control module; the output end of the frequency and inversion factor control module is connected to the second input end of the adaptive frequency multiplier module; the output end of the adaptive frequency multiplier module is connected to the first input end of the output voltage regulation module. Figure 4 A circuit structure diagram of the detection and control module.

[0033] It should be noted that, in the embodiment of the present invention, the differential voltage detection module is used to detect the voltage difference between the two ends of the piezoelectric transducer and input the voltage difference to the voltage-current conversion module. Specifically, the differential voltage detection module is used to detect the voltage difference between the two ends of the piezoelectric transducer V P terminal and V N The voltage difference between the two terminals is obtained by PB -V PA Input to the voltage-current conversion module.

[0034] For example, Figure 5 As shown in Figure 1, the differential voltage detection module consists of two capacitors and four switch tubes (S11~S44). PBdiv(i) and -V NAdiv(i) They are respectively the first input terminal and the second input terminal of the differential voltage detection module, and one end of the switch tube S44 is the output terminal of the differential voltage detection module.

[0035] The voltage-current conversion module is used to convert the received voltage difference into a proportional current signal and input the proportional current signal into the adaptive frequency multiplier module. Specifically, the voltage-current conversion module is used to convert the voltage difference V output by the differential voltage detection module into a proportional current signal. PB -V PA The current signal I is converted into a proportional current signal I, and the proportional current signal I is input into the adaptive frequency multiplier module.

[0036] For example, Figure 6 As shown in the figure, the voltage-current conversion module consists of an amplifier, a PMOS transistor, an NMOS transistor, and a resistor R2. The non-inverting input terminal of the amplifier serves as the input terminal of the voltage-current conversion module, and the gate, source, and drain of the NMOS transistor serve as the output terminal of the voltage-current conversion module.

[0037] The peak voltage detection module is used to detect the positive / negative voltage peak of the piezoelectric transducer output voltage signal. When the positive / negative voltage peak is detected, a pulse signal is generated and sent to the frequency and flip factor control module, and the inherent capacitance C of the piezoelectric transducer is converted to P A first LC resonant circuit is formed with the inductor L, and the energy in the piezoelectric transducer is transferred to the inductor through the first LC resonant circuit, so that the voltage of the piezoelectric transducer begins to reverse. When the current of the inductor passes through zero, the energy stored in the inductor L is reversely transferred to the piezoelectric transducer through the LC resonant circuit, so that the voltage of the piezoelectric transducer stops reversing.

[0038] Specifically, for the above-mentioned Figure 3For example, when the peak voltage detection module detects the positive voltage peak of the piezoelectric transducer PZT output voltage, it generates a falling edge signal, and the output level changes from high to low. At this time, S1, S4 and S8 are triggered to turn on, and the inherent capacitance C of the piezoelectric transducer is P It forms an LC resonant circuit with the inductor L, and transfers the energy in the piezoelectric transducer to the inductor L through the LC resonant circuit, so that the voltage of the piezoelectric transducer begins to flip. When the current of the inductor L is detected to be zero, that is, when the negative voltage peak of the piezoelectric transducer PZT output voltage is detected, a rising edge signal is generated, and the output level changes from a low level to a high level. At this time, S2, S3, and S8 are triggered to turn on, and S1 and S2 are turned off, and the energy stored in the inductor L is reversely transferred to the piezoelectric transducer through the LC resonant circuit, so that the voltage of the piezoelectric transducer ends flipping. Figure 7 As shown, the process of the piezoelectric transducer PZT flipping from the positive voltage peak to the negative voltage is shown by the red solid arrow, and the process of flipping from the negative voltage peak to the positive voltage is shown by the blue solid arrow.

[0039] For example, Figure 8 As shown, the peak voltage detection module consists of transistors M1~M24 and capacitor C IN Among them, transistors M1~M4 constitute an active transconductance amplifier, M5~M8 constitute an output amplifier, M9~M12 constitute an output reverse amplifier, and M13~M24 constitute a reference current part. Among them, V IN The input terminal of the peak voltage detection module, V OUT It is the output end of the peak voltage detection module.

[0040] The following takes negative peak detection as an example to illustrate the working principle of the circuit: In V IN Before reaching its negative peak, V IN Gradually decreases, causing V1 to maintain a low voltage state and V2 to maintain a high voltage. This causes M3 to close and M2 to open. As a result, a current I1 is generated on the capacitor C IN Charging. With V IN Gradually approaching its negative peak, V IN The slope of V gradually decreases, causing I1 to gradually decrease. IN When it reaches its negative peak, I1 decreases to zero and then V IN Starts to increase, V1 gradually rises, V2 drops, driving the node V3 voltage to jump, so that the circuit output flips from low level to high level, generating a rising edge, indicating that the negative peak is detected. At this time, M3 is turned on, M2 is turned off, and the circuit enters the next half cycle, V IN The positive cycle works similarly to the negative cycle, but in the opposite direction.

[0041] The frequency and flip factor control module is used to determine the frequency f of the piezoelectric transducer PZT based on the received pulse signal PZI and voltage reversal factor and the frequency f of the piezoelectric transducer PZT PZI and voltage reversal factor Input to the adaptive frequency multiplier module. Specifically, the frequency and flip factor control module determines the frequency f of the piezoelectric transducer PZT based on the pulse signal output by the peak voltage detection module. PZI and voltage reversal factor and the frequency f of the piezoelectric transducer PZT PZI and voltage reversal factor Input to the adaptive frequency multiplier block.

[0042] The adaptive frequency multiplier module is used to generate a corresponding frequency multiplication signal based on the received proportional current signal, the PZT frequency of the piezoelectric transducer and the voltage reversal factor, and input the frequency multiplication signal to the output voltage regulation module. Specifically, the adaptive frequency multiplier module is based on the proportional current signal I output by the voltage-current conversion module, the frequency and reversal factor control module, and the frequency f of the piezoelectric transducer PZT output. PZI and voltage reversal factor , generating a corresponding frequency-multiplied signal CLK, and inputting the frequency-multiplied signal CLK into the output voltage regulation module.

[0043] For example, Figure 9 As shown in Figure 1, the adaptive frequency multiplier module consists of capacitors C1 and C2, an NMOS transistor, resistor R1, four switching transistors (S55 to S88), and an amplifier. The gate and source of the NMOS transistor serve as the input terminals of the adaptive frequency multiplier module, and the output terminal CLK of the amplifier serves as the output terminal of the adaptive frequency multiplier module.

[0044] In some embodiments, the output voltage regulation module includes: a constant time conduction module, a load detection module, and a zero-crossing detection module.

[0045] The input end of the constant time conduction module is connected to the output end of the detection and control module, and the first output end is connected to the first input end of the logic control module; the input end of the load detection module is connected to the output capacitor C OUT The ungrounded end is connected, and the first output end is connected to the second input end of the logic control module; The first input terminal of the zero-crossing detection module is connected to the V SW1 The first input terminal is connected to the first output terminal of the constant time conduction module, the second output terminal of the constant time conduction module is connected to the third input terminal of the logic control module, and the output terminal is connected to the third input terminal of the logic control module.

[0046] It should be noted that, in the embodiment of the present invention, the constant time conduction module is used to generate a fixed time length switch tube conduction signal T ON1 , to control the on-times of the first, second, third, fourth, fifth, sixth, seventh, eighth, and ninth switching transistors. Specifically, the constant on-time module generates a pulse signal of a fixed duration based on the multiplied frequency signal CLK output by the adaptive frequency multiplier module. The duration of the pulse signal is the on-time of the first, second, third, fourth, fifth, sixth, seventh, eighth, and ninth switching transistors.

[0047] For example, Figure 10 As shown in the figure, the constant-time conduction module consists of an AND gate, three NOT gates, a D flip-flop, an NMOS transistor, a PMOS transistor, a resistor, and a capacitor. The input terminal IN of the D flip-flop is the input terminal of the constant-time conduction module, and OUT is the output terminal of the constant-time conduction module.

[0048] Load detection module, used to detect the output capacitance C OUT The output voltage VOUT of the ungrounded end is OUT When the voltage is less than the threshold, the inductor L and the output capacitor C OUT A second LC resonant circuit is formed, and the energy storage element C is converted from the energy storage element C to the energy storage element C through the second LC resonant circuit. STO Energy is extracted from it to power the load to be powered; when the output voltage V OUT Less than the heavy load reference voltage V REF_HEAVY When the piezoelectric transducer's inherent capacitance CP and the inductor L form a first LC resonant circuit, after the energy in the piezoelectric transducer is transferred to the inductor L through the first LC resonant circuit, the inductor L and the output capacitor C are connected. OUT A second LC resonant circuit is formed, and the energy in the inductor L is transferred to the output capacitor C through the second LC resonant circuit. OUT To power the load to be powered; when the output voltage VOUT is greater than the light load reference voltage V REF_LIGHT When the inherent capacitance C of the piezoelectric transducer is P A first LC resonant circuit is formed with the inductor L, and the energy in the piezoelectric transducer is extracted and stored in the energy storage element through the first LC resonant circuit, thereby optimizing the power transmission path of piezoelectric vibration energy harvesting, suppressing the problem of low end-to-end harvesting efficiency caused by cascade loss, and improving end-to-end efficiency.

[0049] Specifically, for the above-mentioned Figure 3 In terms of the positive half cycle, when the load detection module detects the output voltage V OUT When the voltage is lower than the threshold, S5 and S9 are triggered to conduct, and the energy storage element CSTO Part of the energy in the circuit is transferred to the inductor L. After a fixed time, S7 and S9 are turned on, S5 is turned off, and the inductor L and the output capacitor C are connected. OUT Form an LC resonant circuit to quickly transfer the energy input into the inductor L to the capacitor C OUT To supply power to the load to be powered. Figure 11 As shown, the energy storage element C STO The process of transferring part of the energy in the inductor to the inductor L (charging path of the inductor L) is shown by the blue solid arrow, and the energy transferred into the inductor L is transferred to the capacitor C OUT The process (discharge path of inductor L) is shown as the red solid arrow in the figure.

[0050] When the load detection module detects the output voltage V OUT Less than the heavy load reference voltage V REF_HEAVY When the current is 0, S2, S3 and S8 are turned on, and the inductor L and the inherent capacitance CP in the piezoelectric transducer PZT form an LC resonant circuit to transfer the energy in the piezoelectric device PZT to the inductor L. After a fixed time, S7 and S9 are turned on, S2, S3 and S8 are turned off, and the inductor L and the output capacitor C are connected. OUT Form an LC resonant circuit to quickly transfer the energy transferred into the inductor L to the output capacitor C OUT To provide power to the load to be powered and achieve stable power supply support for the load. Figure 12 As shown in the figure, the process of transferring the energy in the piezoelectric device PZT to the inductor L (charging path of the inductor L) is shown as the blue solid arrow, and the energy transferred into the inductor L is transferred to the capacitor C OUT The process (discharge path of inductor L) is shown as the red solid arrow in the figure.

[0051] When the load detection module detects that the output voltage VOUT is greater than the light load reference voltage V REF_LIGHT In order to prevent overvoltage and improve the energy utilization of the system, S2, S3 and S8 are triggered to turn on, and the inductor L and the inherent capacitance CP in the piezoelectric transducer PZT form an LC resonant circuit to transfer the energy in the piezoelectric device PZT to the inductor L. After a fixed time, S6 and S7 are triggered to turn on, and S2, S3 and S8 are turned off to transfer the energy transferred to the inductor L to the energy storage element C. STO For storage. Figure 13 As shown in the figure, the process of transferring the energy in the piezoelectric device PZT to the inductor L (charging path of the inductor L) is shown as the blue solid arrow, and the energy transferred into the inductor L is transferred to the energy storage element C. STO The process (discharge path of inductor L) is shown as the red solid arrow in the figure.

[0052] For example, Figure 14As shown in the figure, the load detection module consists of an amplifier, a D flip-flop, three NOT gates, an AND gate, an NMOS transistor, a PMOS transistor, a resistor and a capacitor. The inverting input of the amplifier is the input of the load detection module, and the inverting input of the amplifier is used to input the reference voltage V REF_HEAVY and V REF_LIGHT , and the gate's T ON2 The end is the output end of the load detection module.

[0053] The zero-crossing detection module is used to detect whether the current of the inductor L crosses zero. When the current of the inductor L crosses zero, it outputs a shutdown signal T OFF To the logic control module to control the turn-off time of the first switch tube, the second switch tube, the third switch tube, the fourth switch tube, the fifth switch tube, the sixth switch tube, the seventh switch tube, the eighth switch tube and the ninth switch tube. Specifically, the zero-crossing detection module is based on the switch tube conduction signal T output by the constant time conduction module. ON1 And the switch tube conduction signal T output by the load detection module ON2 and V of the inductor L SW1 The voltage at the end is used to detect whether the current of the inductor L passes through zero, so that when the current of the inductor L passes through zero, the pulse output is turned off and the signal T is turned off. OFF , to control the turn-off moments of the first switch tube, the second switch tube, the third switch tube, the fourth switch tube, the fifth switch tube, the sixth switch tube, the seventh switch tube, the eighth switch tube and the ninth switch tube.

[0054] For example, Figure 15 As shown in FIG, the zero-crossing detection module consists of two NOT gates, an AND gate, an amplifier, and a D flip-flop. The two input terminals of the AND gate are the first input terminal and the second input terminal of the zero-crossing detection module, respectively; the non-inverting input terminal of the amplifier is the third input terminal of the zero-crossing detection module; and the output terminal Q of the D flip-flop is the output terminal of the zero-crossing detection module.

[0055] It should be noted that, in the embodiment of the present invention, the three input terminals of the logic control module correspond to the input T ON1 、T ON2 and T OFF The nine output terminals are respectively connected to the gate of S1, the control input terminal of S2, the gate of S3, the control input terminal of S4, and the gates of S5~S9. The logic control module is used to realize the logic timing control of S1~S9.

[0056] In order to illustrate the equivalent impedance of the piezoelectric transducer PZT and the inductor L and the equivalent load impedance of the switch and the energy storage module (also known as the load resistance R L ) are the same, maximum power point tracking can be achieved, and the theoretical formula is deduced as follows: Assume that in half a cycle, the inductor current I PThe accumulated charge is Qe, and the piezoelectric voltage of the piezoelectric transducer PZT at the reversal point (peak) is V P , the voltage reversal factor is , half cycle time is T H .

[0057] The average voltage can be obtained as:

[0058] in, is the piezoelectric peak voltage at the start of the positive half cycle, is the piezoelectric peak voltage at the end of the positive half cycle.

[0059] The inherent capacitance C of the piezoelectric transducer PZT P The amount of charge carried away by discharge is , then the half-cycle output energy is approximately:

[0060] Then the average output power is:

[0061] By output power About Piezoelectric Peak Voltage Taking the derivative and setting it to zero, we can get the optimal :

[0062] The average current in the load resistor RL is:

[0063] By half cycle , is the vibration frequency of the piezoelectric transducer PZT in the negative half cycle, we can get:

[0064] Will Substituting into the above formula, we can get the optimal load impedance:

[0065] For the switch and energy storage module after the inductor L, under the discontinuous conduction model, the equivalent load impedance is:

[0066] in, Indicates the inductance value of the inductor L, Indicates the switching frequency.

[0067] Finally, according to Design the switch on time TON , that is, the conduction signal T ON1 and T ON2 duration to achieve the optimum load impedance Matching is achieved, that is, matching of the equivalent impedance with the equivalent load impedance of the switch and the energy storage module is achieved.

[0068] In summary, the present invention omits the rectifier capacitor required in the traditional parallel synchronous switch inductor energy extraction architecture, that is, the energy generated by the piezoelectric transducer can be supplied to the load to be powered through a single conversion without the need for a rectifier capacitor, effectively suppressing the cascade loss common in traditional multi-stage structures, significantly improving the energy conversion efficiency, reducing the circuit area and system cost, and improving the feasibility of on-chip integration. The circuit also has the characteristics of stable output voltage and small ripple, which is beneficial to improving the power supply performance to the subsequent load.

[0069] Furthermore, by collaboratively controlling the switch on-time and the inductor's charge state, the equivalent impedance of the piezoelectric transducer and inductor is matched to the equivalent load impedance of the switch and energy storage module, enabling maximum power point tracking of piezoelectric energy harvesting and improving energy conversion efficiency. Compared to traditional energy harvesting methods based on weak coupling scenarios (such as synchronous switch induction or synchronous charge extraction), this invention avoids the reliance on large inductors and complex, high-power control circuits, effectively reducing system power consumption and size.

[0070] The above is a further detailed description of the present invention in conjunction with specific preferred embodiments, and the specific implementation of the present invention should not be considered to be limited to these descriptions. For those skilled in the art of the present invention, without departing from the concept of the present invention, several simple deductions or substitutions can be made, which should be considered to fall within the scope of protection of the present invention.

Claims

1. A rectifier interface circuit for collecting piezoelectric vibration energy, characterized in that: include: Piezoelectric transducers, switches and energy storage modules, inductors, and detection and control modules; The piezoelectric transducer is connected to both ends of the switch and the energy storage module; The switch and energy storage module are connected to both ends of the inductor, and the voltage output end is connected to the load to be powered; The detection and control module has a first input end and a third input end connected to one end of the piezoelectric transducer, a second input end and a fourth input end connected to the other end of the piezoelectric transducer, a fifth input end connected to the voltage output end of the switch and energy storage module, a sixth input end connected to one end of the inductor, and an output end connected to the input end of the switch and energy storage module; the detection and control module is used to coordinately control the working state of each switch tube in the switch and energy storage module and the charging state of the inductor, so that the voltage of the piezoelectric transducer is reversed, and the equivalent impedance of the piezoelectric transducer and the inductor is matched with the equivalent load impedance of the switch and energy storage module, so as to maintain the output voltage of the piezoelectric transducer at the maximum power point voltage level.

2. The rectifier interface circuit for piezoelectric vibration energy collection according to claim 1, characterized in that: The switch and energy storage module includes: a first switch tube, having a first end connected to the ground, a second end connected to the first end of the second switch tube and one end of the piezoelectric transducer, and a third end connected to the output terminal CK1 of the detection and control module; The second switch tube has a second end connected to the second end of the fourth switch tube, the second end of the fifth switch tube, the second end of the seventh switch tube, and one end of the inductor, and a third end connected to the output terminal CK2 of the detection and control module; a third switch tube, having a first end connected to ground, a second end connected to one end of the piezoelectric transducer and the first end of the fourth switch tube, and a third end connected to the output terminal CK3 of the detection and control module; The fourth switch tube has a third end connected to the output end CK4 of the detection and control module; The fifth switch tube has a first end connected to the first end of the sixth switch tube and one end of the energy storage element, and a third end connected to the output terminal CK5 of the detection and control module; The sixth switch tube has a second end connected to the second end of the eighth switch tube, the second end of the ninth switch tube, and the other end of the inductor, and a third end connected to the output terminal CK6 of the detection and control module; The seventh switch tube has a first end connected to the ground, and a third end connected to the output terminal CK7 of the detection and control module; The eighth switch tube has a first end connected to the ground, and a third end connected to the output terminal CK8 of the detection and control module; The ninth switch tube, the first terminal and the output capacitor C OUT One end of the connection; The output capacitor C OUT , the end not connected to the ninth switch tube is grounded; The energy storage element has one end that is not connected to the fifth switch tube connected to the ground.

3. The rectifier interface circuit for piezoelectric vibration energy collection according to claim 2, characterized in that: The second switch tube and the fourth switch tube include: a transmission gate and an inverter; The control input end of the transmission gate is connected to the input end of the inverter, and the inverting control input end of the transmission gate is connected to the output end of the inverter; wherein, the data input end of the transmission gate is the first end of the second switch tube or the fourth switch tube, the data output end of the transmission gate is the second end of the second switch tube or the fourth switch tube, and the control input end of the transmission gate is the third end of the second switch tube or the fourth switch tube.

4. The rectifier interface circuit for piezoelectric vibration energy collection according to claim 2, characterized in that: The detection and control module includes: a signal detection and flip control module, having a first input end connected to one end of the piezoelectric transducer, a second input end connected to the other end of the piezoelectric transducer, and an output end connected to the first input end of the output voltage regulation module; The output voltage regulating module, the second input terminal and the output capacitor C OUT The ungrounded end is connected to the third input end and one end of the inductor is connected, and the first output end, the second output end and the third output end are connected to the first input end, the second input end and the third input end of the logic control module respectively; The logic control module has a first output terminal CK1 connected to the third end of the first switch tube, a second output terminal CK2 connected to the third end of the second switch tube, a third output terminal CK3 connected to the third end of the third switch tube, a fourth output terminal CK4 connected to the third end of the fourth switch tube, a fifth output terminal CK5 connected to the third end of the fifth switch tube, a sixth output terminal CK6 connected to the third end of the sixth switch tube, a seventh output terminal CK7 connected to the third end of the seventh switch tube, an eighth output terminal CK8 connected to the third end of the eighth switch tube, and a ninth output terminal CK9 connected to the third end of the ninth switch tube.

5. The rectifier interface circuit for piezoelectric vibration energy collection according to claim 4, characterized in that: The signal detection and flip control module includes: a differential voltage detection module, having a first input end connected to one end of the piezoelectric transducer, a second input end connected to the other end of the piezoelectric transducer, and an output end connected to the input end of the voltage-current conversion module; a voltage-current conversion module, an output end of which is connected to the first input end of the adaptive frequency multiplier module; a peak voltage detection module, having a first input end connected to one end of the piezoelectric transducer, a second input end connected to the other end of the piezoelectric transducer, and an output end connected to the input end of the frequency and inversion factor control module; The frequency and flip factor control module has an output end connected to the second input end of the adaptive frequency multiplier module; The output end of the adaptive frequency multiplier module is connected to the first input end of the output voltage regulation module.

6. The rectifier interface circuit for piezoelectric vibration energy collection according to claim 4, characterized in that: The output voltage regulation module includes: a constant time conduction module, wherein the input end is connected to the output end of the detection and control module, and the first output end is connected to the first input end of the logic control module; Load detection module, the input terminal and the output capacitor C OUT The ungrounded end is connected, and the first output end is connected to the second input end of the logic control module; A zero-crossing detection module has a first input connected to one end of the inductor, a second input connected to the second output of the constant-time conduction module, a third input connected to the second output of the load detection module, and an output connected to the third input of the logic control module.

7. The rectifier interface circuit for collecting piezoelectric vibration energy according to claim 5, characterized in that: The differential voltage detection module is used to detect the voltage difference between the two ends of the piezoelectric transducer and input the voltage difference to the voltage-current conversion module; The voltage-current conversion module is used to convert the received voltage difference into a proportional current signal, and input the proportional current signal into the adaptive frequency multiplier module; The peak voltage detection module is used to detect the positive / negative voltage peak of the voltage signal output by the piezoelectric transducer. When a positive / negative voltage peak is detected, a pulse signal is generated and sent to the frequency and inversion factor control module, and the inherent capacitance C of the piezoelectric transducer is P forming a first LC resonant circuit with the inductor, and transferring energy in the piezoelectric transducer to the inductor through the first LC resonant circuit, so that the voltage of the piezoelectric transducer begins to reverse; and when the current of the inductor passes through zero, reversely transferring the energy stored in the inductor to the piezoelectric transducer through the LC resonant circuit, so that the voltage of the piezoelectric transducer stops reversing; The frequency and inversion factor control module is used to determine the frequency and voltage inversion factor of the piezoelectric transducer based on the received pulse signal, and input the frequency of the piezoelectric transducer and the voltage inversion factor into the adaptive frequency multiplier module; The adaptive frequency multiplier module is used to generate a corresponding frequency multiplier signal based on the received proportional current signal, the frequency of the piezoelectric transducer and the voltage reversal factor, and input the frequency multiplier signal to the output voltage regulation module.

8. The rectifier interface circuit for collecting piezoelectric vibration energy according to claim 6, characterized in that: The constant time conduction module is used to generate a fixed time switch tube conduction signal T ON , to control the conduction time of the first switch tube, the second switch tube, the third switch tube, the fourth switch tube, the fifth switch tube, the sixth switch tube, the seventh switch tube, the eighth switch tube and the ninth switch tube.

9. The rectifier interface circuit for collecting piezoelectric vibration energy according to claim 6, characterized in that: The load detection module is used to detect the output capacitance C OUT The output voltage V at the ungrounded end OUT , when the output voltage V OUT When the voltage is less than the threshold, the inductor and the output capacitor C OUT A second LC resonant circuit is formed, and energy is extracted from the energy storage element through the second LC resonant circuit to supply power to the load to be powered; when the output voltage V OUT When the voltage is less than the heavy-load reference voltage, the inherent capacitance C of the piezoelectric transducer P A first LC resonant circuit is formed with the inductor, and after the energy in the piezoelectric transducer is transferred to the inductor through the first LC resonant circuit, the inductor is connected to the output capacitor C OUT The second LC resonant circuit is formed, and the energy in the inductor is transferred to the output capacitor C through the second LC resonant circuit. OUT to supply power to the load to be powered; when the output voltage VOUT is greater than the light-load reference voltage, the inherent capacitance C of the piezoelectric transducer is P A first LC resonant circuit is formed with the inductor, and energy in the piezoelectric transducer is extracted to the energy storage element through the first LC resonant circuit for storage.

10. The rectifier interface circuit for collecting piezoelectric vibration energy according to claim 6, characterized in that: The zero-crossing detection module is configured to detect whether the current of the inductor crosses zero, and output a shutdown signal to the logic control module when the current of the inductor crosses zero, so as to control the shutdown moments of the first, second, third, fourth, fifth, sixth, seventh, eighth, and ninth switching tubes.

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