CN111277169B

CN111277169B - Interface circuit for piezoelectric energy collection, control unit and method thereof

Info

Publication number: CN111277169B
Application number: CN202010073359.7A
Authority: CN
Inventors: 于玮玮; 王莉菲
Original assignee: Huada Semiconductor Co ltd
Current assignee: Huada Semiconductor Co ltd
Priority date: 2020-01-20
Filing date: 2020-01-20
Publication date: 2024-04-19
Anticipated expiration: 2040-01-20
Also published as: CN111277169A

Abstract

The invention provides an interface circuit for collecting piezoelectric energy, which comprises a control unit, wherein the control unit is used for controlling a switch connected in series with an energy storage element of a piezoelectric element to be conducted at a proper time and controlling the conduction time of the switch, so that the positive voltage and the negative voltage of the piezoelectric element can be quickly turned over within the conduction time of the switch, the bias turning over can be realized, and the piezoelectric energy can be collected. The control unit is further used for controlling the switch to be conducted according to the half-cycle point moment of the change of the positive voltage and the negative voltage, and conducting for a preset time, and/or controlling the switch to be conducted when the positive voltage or the negative voltage reaches an extreme value, and when the positive voltage or the negative voltage rises to a preset voltage value, disconnecting the switch to control the conducting time, wherein the preset time is far smaller than the change period of the positive voltage and the negative voltage, or the preset voltage value is the partial pressure of the rectified voltage of the interface circuit, so that oscillation is prevented, and rapid overturning is realized, and the energy collecting efficiency is improved.

Description

Interface circuit for piezoelectric energy collection, control unit and method thereof

Technical Field

The invention relates to the field of piezoelectric energy collection, in particular to an interface circuit for realizing piezoelectric energy collection of parallel inductance synchronous switch collection (Parallel Synchronized SWITCH HARVESTING on Inductor (P-SSHI)) technology, and a control unit and a control method thereof.

Background

The quality of the rectifier interface circuit is a key to how much piezoelectric energy is collected. While rectifiers employing P-SSHI technology can collect more energy than rectifiers employing simple diode construction, current implementation of P-SSHI functionality is largely aided by board-set design and micro-control units (Microcontroller Unit (MCU)) employing discrete components.

Disclosure of Invention

It is an object of the present invention to provide an interface circuit for piezoelectric energy harvesting, which can be used in P-SSHI technology, and a control unit and method thereof.

According to one aspect of the present invention, there is provided an interface circuit for piezoelectric energy harvesting, comprising a control unit for generating a conduction control signal for controlling conduction of a switch in series with an energy storage element of the piezoelectric element and for controlling conduction of the switch for a period of time such that a positive voltage and a negative voltage of the piezoelectric element are rapidly flipped over during the period of time in which the switch is conducting, to maximize piezoelectric energy harvesting.

The interface circuit according to the above aspect of the present invention, wherein the control unit is further configured to set the time at which the switch is turned on by a period of change according to the positive voltage and the negative voltage and/or by the positive voltage or the negative voltage reaching an extreme value; and/or the switch is turned off for a preset time after the switch is turned on, and/or the switch is turned off to control the on time period by detecting the rising edge of the positive voltage or the negative voltage and when the positive voltage or the negative voltage rises to a preset voltage value; and/or the preset voltage value is the voltage division of the voltage rectified by the interface circuit; and/or the preset time corresponds to half of a resonance period of the equivalent capacitance of the energy storage element and the piezoelectric element.

An interface circuit according to the above aspect of the present invention, wherein the control unit includes comparing means for comparing the positive electrode voltage and/or the negative electrode voltage with the voltage rectified by the interface circuit and with a ground level to generate one or more of first to fourth control signals, respectively; and/or first detection means for judging whether the positive electrode voltage or the negative electrode voltage is at a rising edge by one or more of the first to fourth control signals to give a first detection signal and a second detection signal; the second detection device is used for comparing the positive electrode voltage or the negative electrode voltage at the rising edge with a preset voltage value to detect whether the positive electrode voltage or the negative electrode voltage rises to the preset voltage value or not so as to obtain a third detection signal; and/or third detection means for determining whether the inversion of the positive electrode voltage and the negative electrode voltage is ended by the third detection signal to obtain an inversion detection signal; and/or a conduction control signal generating device for generating a conduction control signal for controlling the switch connected in series with the energy storage element according to the first detection signal, the second detection signal and the inversion detection signal.

According to the interface circuit of the above aspect of the present invention, the control unit further includes first to fourth comparators for comparing the positive electrode voltage and/or the negative electrode voltage with the voltage rectified by the interface circuit and comparing with the ground level to generate first to fourth control signals, respectively; and/or first and second D flip-flops for determining whether the positive electrode voltage or the negative electrode voltage is at a rising edge by one or more of the first to fourth control signals to give a first detection signal and a second detection signal, respectively; a fifth comparator for comparing the positive voltage or the negative voltage at the rising edge with a preset voltage value to detect whether the positive voltage or the negative voltage rises to the preset voltage value or not so as to give a third detection signal; and/or a first or gate for generating a reset control signal by logically or-ing the first and second control signals or by logically or-ing the third and fourth control signals; and/or a third D trigger, which is used for determining the end of the turning of the positive electrode voltage and the negative electrode voltage through the third detection signal and the reset control signal so as to give a turning detection signal; and/or a first AND gate for logically AND the flip detection signal with the first detection signal; and/or a second AND gate for logically AND the flip detection signal with the second detection signal; and/or a second or gate for logically or-ing the result of the first and gate with the result of the second and gate to generate a conduction control signal for controlling the switch in series with the energy storage element.

The interface circuit according to the above aspect of the present invention further includes a switching circuit connected to the control unit, the switching circuit including first to fourth switches that are turned on or off by the first to fourth control signals, respectively; and/or any one of the first to fourth switches is a diode; and/or any one of the first to fourth switches comprises a diode, a selective switching tube; and/or the selective switch tube comprises a triode, a transistor and a metal oxide semiconductor tube; and/or the first to fourth switches are used to construct a full-wave rectifier bridge that converts the alternating voltage of the positive and negative voltages to a direct voltage.

According to the interface circuit of the above aspect of the present invention, the control unit further comprises a first comparator for comparing the rectified voltage with the positive voltage to obtain a first control signal, and/or the first control signal controls the first switch to be turned on at V _P≥V_rect and turned off at V _P＜V_rect; and/or a second comparator for comparing the rectified voltage with the negative voltage to obtain a second control signal, and/or the second control signal controls the second switch to be turned on when V _N≥V_rect and the second control signal controls the second switch to be turned off when V _N＜V_rect; a third comparator for comparing the ground level with the negative voltage to obtain a third control signal, and/or when V _N is less than or equal to 0, the third control signal controls the third switch to be turned on, and when V _N is more than 0, the third control signal controls the third switch to be turned off; and/or a fourth comparator for comparing the ground level with the positive voltage to obtain a fourth control signal, and/or when V _P is less than or equal to 0, the fourth control signal controls the fourth switch to be turned on, and when V _P is more than 0, the fourth control signal controls the fourth switch to be turned off, wherein V _P is the positive voltage, V _N is the negative voltage, and V _rect is the rectified voltage.

According to another aspect of the present invention, there is provided a control unit for an interface circuit for piezoelectric energy harvesting, comprising conduction control signal generating means for generating a conduction control signal for controlling conduction of the switch in series with an energy storage element such that a positive voltage-negative voltage of the piezoelectric element is rapidly flipped over during a conduction time of the switch to maximize piezoelectric energy harvesting.

According to the control unit of the above aspect of the present invention, the conduction control signal generating means is configured to set the conduction control signal that turns on the switch every time a half-cycle time point of the positive electrode voltage or the negative electrode voltage corresponding to the maximum point of deformation of the piezoelectric element is reached, in accordance with a variation cycle of the positive electrode voltage and the negative electrode voltage, and turns off after the on time; and/or generating the conduction control signal by detecting an extreme value of the positive voltage or the negative voltage and detecting that the positive voltage or the negative voltage rises from the extreme value to a preset voltage value at the rising edge so as to control the conduction time; and/or the preset voltage value is the divided voltage of the rectified voltage of the interface circuit; and/or the extremum corresponds to a critical point at which the positive or negative voltage begins to invert; and/or the on time corresponds to half of a resonance period of the equivalent capacitance of the energy storage element and the piezoelectric element or corresponds to a time when the positive voltage or the negative voltage rises from the lowest value of the positive voltage or the negative voltage to the preset voltage value.

The control unit according to the above aspect of the present invention further comprises comparing means for comparing the positive electrode voltage and/or the negative electrode voltage with the voltage rectified by the interface circuit and with a ground level to generate one or more of the first to fourth control signals, respectively; and/or first detection means for detecting that the positive electrode voltage or the negative electrode voltage is at a rising edge by one or more of the first to fourth control signals to obtain a first detection signal and a second detection signal; the second detection device is used for comparing the positive electrode voltage or the negative electrode voltage at the rising edge with a preset voltage value to detect whether the positive electrode voltage or the negative electrode voltage rises to the preset voltage value or not so as to obtain a third detection signal; and/or third detection means for determining the end of the inversion of the positive electrode voltage and the negative electrode voltage by the third detection signal to give an inversion detection signal; and/or the conduction control signal generating device is used for generating a conduction control signal for controlling the switch connected with the energy storage element in series according to the first detection signal, the second detection signal and the turnover detection signal.

The control unit according to the above aspect of the present invention further includes first to fourth comparators for comparing the positive electrode voltage and/or the negative electrode voltage with the voltage rectified by the interface circuit and comparing with a ground level to generate first to fourth control signals, respectively; and/or first and second D flip-flops for detecting whether a positive electrode voltage or a negative electrode voltage is at a rising edge by one or more of the first to fourth control signals to obtain a first detection signal and a second detection signal, respectively; a fifth comparator for comparing the positive voltage or the negative voltage at the rising edge with a preset voltage value to detect whether the positive voltage or the negative voltage rises to the preset voltage value or not, so as to obtain a third detection signal; and/or a third D trigger for determining the end of the positive voltage and the negative voltage inversion by the third detection signal to give an inversion detection signal; and/or a first AND gate for logically AND the flip detection signal with the first detection signal; and/or a second AND gate for logically AND the flip detection signal with the second detection signal; and/or a second or gate for logically or-ing the result of the first and second and gate to generate a conduction control signal for controlling the switch of the energy storage element in series.

A control unit according to the above aspect of the present invention, wherein first to fourth switches of the interface circuit are controlled to be turned on or off by the first to fourth control signals, respectively; and/or any one of the first to fourth switches is a diode; and/or any one of the first to fourth switches comprises a diode, a selective switching tube; and/or the selective switch tube comprises a triode, a transistor and a metal oxide semiconductor tube; and/or the first to fourth switches are used to construct a full-wave rectifier bridge that converts the alternating voltage of the positive and negative voltages to a direct voltage.

According to the control unit of the above aspect of the present invention, the control unit is further configured to compare the rectified voltage with the positive voltage to obtain a first control signal, and/or the first control signal controls the first switch to be turned on at V _P≥V_rect and controls the first switch to be turned off at V _P＜V_rect; and/or a second comparator for comparing the rectified voltage with the negative voltage to obtain a second control signal, and/or the second control signal controls the second switch to be turned on when V _N≥V_rect and the second control signal controls the second switch to be turned off when V _N＜V_rect; a third comparator for comparing the ground level with the negative voltage to obtain a third control signal, and/or when V _N is less than or equal to 0, the third control signal controls the third switch to be turned on, and when V _N is more than 0, the third control signal controls the third switch to be turned off; and/or a fourth comparator for comparing the ground level with the positive voltage to obtain a fourth control signal, and/or when V _P is less than or equal to 0, the fourth control signal controls the fourth switch to be turned on, and when V _P is more than 0, the fourth control signal controls the fourth switch to be turned off, wherein V _P is the positive voltage, V _N is the negative voltage, and V _rect is the rectified voltage.

According to yet another aspect of the present invention, there is provided a method comprising generating a conduction control signal for controlling a switch connected in series with an energy storage element of the piezoelectric element to be turned on at a timing corresponding to a deformation of the piezoelectric element to a maximum point and controlling a conduction time of the switch so that a positive electrode voltage and a negative electrode voltage of the piezoelectric element are rapidly inverted within the conduction time of the switch to achieve bias inversion, and collecting piezoelectric energy.

According to the method of the above aspect of the invention, wherein the time at which the piezoelectric element deforms to the maximum point corresponds to the time at which each half cycle point of the change in the positive electrode voltage or the negative electrode voltage passes or when the positive electrode voltage or the negative electrode voltage reaches an extreme value, the method further includes controlling the on time to be much smaller than the period of the change in the positive electrode voltage and the negative electrode voltage of the piezoelectric element; and/or determining whether the positive voltage or the negative voltage rises to a preset voltage value by detecting the rising edge of the positive voltage or the negative voltage of the piezoelectric element so as to open the switch, wherein the preset voltage value is the voltage division of the rectified positive voltage and the rectified negative voltage.

The method according to the above aspect of the invention further comprises determining whether the on-time of the switch has arrived, controlling the switch of the series connection of energy storage elements to be turned off in response to the on-time having ended, and/or keeping the switch of the series connection of energy storage elements on in response to the on-time not having ended; and/or judging whether the positive voltage or the negative voltage rises to the preset voltage value after the switch is conducted, and responding to the fact that the positive voltage or the negative voltage does not rise to the preset voltage value, keeping the switch connected in series with the energy storage element to be conducted; and/or in response to the positive voltage or the negative voltage rising to the preset voltage value, controlling a switch connected in series with the energy storage element to be disconnected.

The method according to the above aspect of the present invention further includes generating first to fourth control signals by comparing the positive electrode voltage or the negative electrode voltage with the rectified voltage and with a ground level; and/or controlling on or off of first to fourth switches of the switching circuit for piezoelectric energy collection using the first to fourth control signals, respectively; and/or generating first to fourth control signals and/or a conduction control signal for controlling the conduction or disconnection of a switch connected in series with the energy storage element by processing the positive voltage, the negative voltage and/or the rectified voltage.

According to still another aspect of the present invention, there is provided a method including detecting whether a positive electrode voltage or a negative electrode voltage of a piezoelectric element rises to a preset voltage value when the positive electrode voltage and the negative electrode voltage are inverted; and/or generating a conduction control signal for opening a switch for connecting the energy storage elements of the piezoelectric element in series in response to detecting that the positive voltage or the negative voltage rises to the preset voltage value.

According to the method of the above aspect of the present invention, the on control signal is further used to control the switch to be turned on at a time corresponding to the maximum deformation of the piezoelectric element and to control the switch to be turned off when the positive voltage or the negative voltage rises to a preset voltage value after being turned on, so as to realize rapid overturn of the positive voltage and the negative voltage; and/or the preset voltage value may include a divided voltage using a voltage rectified by a switching circuit of the piezoelectric element.

The method according to the above aspect of the present invention further includes comparing the rectified voltage with the positive voltage or the negative voltage and comparing with a ground level to generate first to fourth control signals; and/or detecting rising edges of the positive electrode voltage or the negative electrode voltage by the first to fourth control signals to obtain a first detection signal and a second detection signal, respectively; and/or selectively comparing the negative voltage or the positive voltage with the preset voltage value according to the first detection signal and the second detection signal to generate a third detection signal; and/or detecting whether the positive voltage and the negative voltage are in a flipping ready state by judging whether one of the positive voltage and the negative voltage is greater than the rectified voltage or whether one of the positive voltage and the negative voltage is less than a ground level to generate a reset control signal; and/or generating a flip detection signal according to the third detection signal and the reset control signal.

The method according to the above aspect of the present invention further comprises, in response to detecting that the positive voltage or the negative voltage does not rise to the preset voltage value, causing the inversion detection signal to have a first level to indicate that inversion has not ended; and/or in response to the positive voltage or the negative voltage rising to the preset voltage value, enabling the inversion detection signal to have a second level lower than the first level; and/or in response to detecting that one of the positive voltage and the negative voltage is greater than the rectified voltage or one of the positive voltage and the negative voltage is less than the ground level, the inversion detection signal is made to have a first level corresponding to the positive voltage and the negative voltage being in an inversion ready state; and/or generating the on control signal according to the first detection signal, the second detection signal and the flip detection signal; and/or the inversion detection signal is logically and-ed with the first detection signal and the second detection signal respectively, and the result of the logical and is logically or-ed to obtain the conduction control signal.

According to yet another aspect of the present invention there is provided a non-transitory machine readable storage medium comprising one or more instructions, characterized in that the one or more instructions, in response to being executed, cause one or more processing modules to perform one or more steps of a method according to the above aspect of the present invention.

According to yet another aspect of the present invention, there is provided a control apparatus comprising one or more processing modules; one or more memory modules coupled with the one or more processing modules, the memory modules for storing one or more instructions that, in response to being executed, cause the one or more processing modules to carry out one or more steps of the methods described in the above aspects of the invention.

According to the above aspect of the present invention, by controlling the switch connected in series with the energy storage element of the piezoelectric element to be turned on and controlling the switch to be turned off after being turned on for a period of time, wherein the on period is far less than the variation period of the positive voltage or the negative voltage, the positive voltage and the negative voltage are rapidly turned over without oscillation, so that the effect of improving the energy collection efficiency is achieved, and the piezoelectric energy collection is performed to the maximum. In addition, according to another embodiment of the present invention, the switching on and off of the rectifier bridge of the piezoelectric energy collection interface circuit can be controlled, so that piezoelectric or vibration energy collection can be performed to achieve the effect of reducing energy loss. According to the above aspects of the present invention, the fully integrated circuit can be utilized to implement the P-SSHI function autonomously without requiring an additional MCU to implement the control logic.

Drawings

FIG. 1 shows a schematic diagram of a piezoelectric energy harvesting interface circuit according to one embodiment of the invention;

FIG. 2 shows a schematic diagram of a piezoelectric energy harvesting interface circuit according to another embodiment of the invention;

FIG. 3 shows a schematic diagram of a control unit that may be used for piezoelectric energy harvesting in accordance with one embodiment of the present invention;

FIG. 4 shows a schematic diagram of simulated waveforms of a piezoelectric energy harvesting interface circuit, according to one embodiment of the invention;

FIG. 5 illustrates an enlarged schematic diagram corresponding to the simulated waveforms shown in FIG. 4, in accordance with one embodiment of the present invention;

FIG. 6 shows a schematic flow chart diagram of a method in accordance with one embodiment of the present invention;

FIG. 7 shows a schematic flow chart of a method according to another embodiment of the invention;

FIG. 8 shows a schematic flow chart of a method according to yet another embodiment of the invention;

fig. 9 shows a schematic diagram of an example apparatus according to yet another embodiment of the invention.

Detailed Description

The present invention will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present invention more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention.

While the following description sets forth various implementations that may be illustrated, for example, in a system architecture, implementations of the techniques and/or arrangements described herein are not limited to a particular system architecture and/or computing system, and may be implemented with any architecture and/or computing system for similar purposes. For example, the techniques and/or arrangements described herein may be implemented with various architectures and/or various computing devices and/or electronic devices, such as one or more integrated circuit chips and/or packages. Furthermore, while the following description may set forth numerous specific details (e.g., logical implementations, types, and interrelationships of system components, logical partitioning/integration choices, etc.), the claimed subject matter may be practiced without these specific details. In other instances, some materials (e.g., control structures and complete software instruction sequences) may not be shown in detail in order not to obscure the materials disclosed herein. The materials disclosed herein may be implemented in hardware, firmware, software, or any combination thereof.

The materials disclosed herein may also be implemented as instructions stored on a machine-readable medium or memory that can be read and executed by one or more processors. A computer-readable medium may include any medium and/or mechanism for storing or transmitting information in a form readable by a machine (e.g., a computing device). For example, a machine-readable medium may include Read Only Memory (ROM), random Access Memory (RAM), magnetic disk storage media; an optical storage medium; a flash memory device; and/or other media. In another form, a non-volatile article (e.g., a non-volatile computer readable medium) may be used in any of the examples mentioned above or in other examples, including those elements (e.g., RAM, etc.) which may temporarily store data in a "transitory" manner.

Fig. 1 shows a schematic diagram of an example of a piezoelectric energy harvesting interface circuit according to an embodiment of the invention. In one embodiment, the interface circuit 100 may be used to implement piezoelectric energy harvesting for P-SSHI technology. The interface circuit 100 may employ a fully integrated circuit design to autonomously implement P-SSHI technology without requiring an additional MCU to implement control logic.

Referring to fig. 1, the interface circuit 100 may include a control unit 102 connected in parallel with a piezoelectric element 110. As shown in fig. 1, the piezoelectric element 110 may be equivalently a current source 112 connected in parallel with a capacitor 114. In one embodiment, the control unit 102 may detect an extremum (e.g., corresponding to a minimum or maximum value of the positive voltage or the negative voltage) or a period of change of the positive voltage V _P and/or the negative voltage V _N of the piezoelectric unit 110. When the voltages V _P and/or V _N are at the extreme values or each time a 1/2 variation period passes, the control unit 102 may control the switch 104 (S0 shown in fig. 1) connected (e.g., in series) with the energy storage element 106 (e.g., the inductor 106, etc.) to be turned on, and after a predetermined on time, turn off the switch 104 to prevent oscillation, implement rapid inversion, and improve energy collection efficiency. In one embodiment, the inductor 106 may be in parallel with the control unit 102, but in other embodiments the inductor 106 may have a form (not shown) in series with the control unit 102. In one embodiment, inductor 106 and switch 104 may be used to implement the bias flip function of P-SSHI.

In one embodiment, the control unit 102 may control the on-time of the switch 104 by at least the following two methods (a) and/or (B), but the invention is not limited thereto:

(A) In one embodiment, the on-time of the switch 104 may be controlled by a predetermined time. For example, the preset time may be set according to the vibration periods of V _P and V _N (e.g., the variation periods of the voltages V _P and V _N). For example, the control unit 102 may turn on the switch 104 every 1/2 period of the voltages V _P and V _N (e.g., corresponding to the deformation of the piezoelectric element 110 to a maximum point) and turn off the switch 104 after a conduction time (which is much less than the period of change in V _P and V _N, as shown in fig. 4 or 5). In one embodiment, the preset on-time corresponds to half of the resonance period of the equivalent capacitance of the energy storage element and the piezoelectric element, but the present invention is not limited thereto, and in other embodiments, the on-time may have a value much smaller than the variation period of the voltages V _P and V _N. In another embodiment, the on-time may be set to substantially correspond to the flip time of V _P or V _N; and/or

(B) In another embodiment, an extremum of voltage V _P or V _N may be detected. For example, when the voltages V _P and V _N reach an extreme value (e.g., as shown at 404 or 406 of fig. 5, which corresponds to a critical point at which the voltages V _P or V _N will fall from, for example, a maximum value or rise or start to flip from a minimum value, or the piezoelectric element 110 reaches a maximum deformation), the control unit 102 may turn on the switch 104, at which time V _P and V _N start to flip, and when V _P or V _N rises to a preset voltage value (e.g., the partial voltage v_f of the rectified voltage V _rect), the control unit 102 may control to turn off the switch 104.

For example, the control unit 102 may control the on/off of the switch 104 connected (e.g., in series) with the inductor 106 using an on control signal ctrl0. The control unit 102 may generate first to fourth control signals ctrl1 to ctrl4 for controlling the first to fourth switches and/or a turn-on control signal ctrl0 for controlling the switch 104 by processing the input voltage signal V _P、V_N and the rectified voltage V _rect. Referring to fig. 4 and 5, in one embodiment, during the fast flip of V _P and V _N as indicated by the dashed box 402, the on control signal ctrl0 is at a high level, when the switch 104 is on, the switch 104 is on for a period of time, the switch 104 is off, and the fast flip of V _P and V _N is terminated, wherein the on time is substantially less than the period of change of V _P and V _N. In another embodiment, during the fast inversion of V _P and V _N, the on control signal ctrl0 is at a high level, when the switch 104 is on, ctrl0 goes low at the rising edge of the voltage V _P or V _N (e.g., when V _P or V _N rises to a preset voltage value), thereby turning the switch 104 off.

As shown in fig. 1, the interface circuit 100 may further include a switch circuit 120. For example, the switching circuit 120 may include a rectifier bridge, but the present invention is not limited thereto. The bridge circuit of the rectifier bridge may include first through fourth switches 122 through 128 (e.g., S1, S2, S3, and S4 shown in fig. 1). The first through fourth switches 122 through 128 may be used to convert the ac voltage of the voltage V _P and/or V _N of the piezoelectric element 110 to a dc voltage V _rect for storage on the rectifying capacitor 108 (C _rect shown in fig. 1) to collect piezoelectric and/or vibrational energy to reduce energy losses. In one embodiment, the first through fourth switches 122 through 128 may constitute a full-wave rectifier bridge. In one embodiment, the first through fourth switches 122 through 128 may include diodes.

In one embodiment, the first through fourth switches 122 through 128 may be used to provide a temporary conduction path through the switching circuit 120.

Fig. 1 illustrates only one example of a piezoelectric energy harvesting interface circuit that may be used to implement the P-SSHI function, and in other embodiments, interface circuits having other structures may be utilized.

Fig. 2 shows a schematic diagram of an example of an interface circuit according to another embodiment of the invention. The interface circuit 200 shown in fig. 2 may be used to implement piezoelectric energy harvesting for P-SSHI functions. The interface circuit can be designed by a fully integrated circuit, so that the P-SSHI function can be autonomously realized, and an additional MCU is not needed to realize control logic.

Similar to the interface circuit 100 of fig. 1, the interface circuit of fig. 2 may include a control unit 202 in parallel with the piezoelectric element 110, an inductor 106 (or other energy storage element, etc.) in parallel or series with the control unit 202 (not shown), a switch 104 coupled to the inductor 106, a switching circuit 220 (e.g., including first through fourth switches 222 through 228) that may be controlled to be turned on and off by the control unit 202, and/or a capacitor 108 (C _rect) for storing a dc voltage V _rect converted from an ac voltage of V _P and V _N.

In one embodiment, the switching circuit 220 may include a rectifier bridge, but the present invention is not limited thereto. Any of the first through fourth switches 222 through 228 may include diodes and/or selectively switched transistors. For example, the selective switch may include a transistor, a metal oxide semiconductor (metal oxide semiconductor (MOS)) transistor, and the like, but the present invention is not limited thereto. In other embodiments, one or more of the first through fourth switches 222 through 228 may include a diode, and the remaining switches may include a selective switching tube, but the present invention is not limited thereto.

Similar to that described in fig. 1, the first through fourth switches 222 through 228 may be used for piezoelectric and/or vibrational energy harvesting to reduce energy losses. For example, the first through fourth switches 222 through 228 may form a full-wave rectifier bridge to convert the ac voltage of the piezoelectric voltage V _P and/or V _N of the piezoelectric element 110 to the dc voltage V _rect for storage on the rectifying capacitor 108 (C _rect shown in fig. 1).

As shown in fig. 2, in one embodiment, the control unit 202 may control the on-time of the switch 104 at least by two methods (a) and/or (B) as described above to achieve fast flipping of V _P and V _N without oscillation, and improve the energy collection efficiency. The control unit 202 may also be used to control the switching on and off of the switching circuit 220 to reduce energy consumption.

As shown in fig. 2, the control unit 202 may control the on and off of the first to fourth switches 222 to 228 of the switching circuit 220 and/or the on and off of the switch 104 connected to the inductor 106 using the first to fourth logic signals ctrl1, ctrl2, ctrl3, ctrl4 and the on control signal ctrl0, respectively. In one embodiment, the control unit 202 may generate the first to fourth logic signals ctrl1 to ctrl4 and/or the turn-on control signal ctrl0 by processing the input voltage signal V _P、V_N and the rectified voltage V _rect (e.g., as shown in fig. 3). In another embodiment, the control unit 202 may generate control signals for controlling the turning on and off of the respective selective switching tubes, respectively.

As shown in fig. 2, the control unit 202 may be configured to generate the first control signal ctrl1 by comparing V _rect with V _P, wherein ctrl1 controls S1 to be turned on when V _P≥V_rect, and ctrl1 controls S1 to be turned off when V _P＜V_rect.

The control unit 202 may be further configured to generate the second control signal ctrl2 by comparing V _rect with V _N such that ctrl2 controls S2 to be on when V _N≥V_rect and ctrl2 controls S2 to be off when V _N＜V_rect.

The control unit 202 may also be configured to generate a third control signal ctrl3 by comparing the signal ground (0 level) with V _N, wherein ctrl3 controls S3 to be on when V _N is less than or equal to 0, and ctrl3 controls S3 to be off when V _N is greater than 0.

The control unit 202 may be further configured to obtain a fourth control signal ctrl4 by comparing the signal ground (0 level) with V _P, wherein ctrl4 controls S4 to be turned on when V _P is less than or equal to 0, and ctrl4 controls S4 to be turned off when V _P is greater than 0.

Fig. 2 illustrates only one example of a piezoelectric energy harvesting interface circuit that may be used to implement the P-SSHI function, and in other embodiments, interface circuits having other structures may be utilized.

Fig. 3 shows a schematic diagram of an example of a control unit according to an embodiment of the invention. In one embodiment, the control unit 300 may be configured to control the on and/or off of the switch 104 of fig. 1 or 2 to implement the method (B) described above. The control unit 300 may be used to control the switching circuit 200 shown in fig. 2. Fig. 4 and 5 illustrate examples of timing diagrams of one or more control signals corresponding to the control unit shown in fig. 3, according to one embodiment of the invention. The control unit shown in fig. 3 is described below with reference to fig. 4 and 5, but the timing chart is not a limitation of the present invention.

As shown in fig. 3, in one embodiment, the control unit 300 comprises comparing means for comparing V _P and/or V _N with the rectified voltage V _rect and with ground level to generate one or more of the first to fourth control signals, respectively. The comparing means comprises a first comparator 302, a second comparator 304, a third comparator 306 and/or a fourth comparator 308.

The first comparator 302 may be configured to compare the dc voltage V _rect with the positive voltage V _P to obtain a first control signal ctrl1 for controlling the first switch 222 (S1) shown in fig. 2. When V _P≥V_rect, the first control signal ctrl1 (e.g., high or logic 1) may control the first switch 222 to be turned on, and when V _P＜V_rect, the first control signal ctrl1 (e.g., low or logic 0) may control the first switch 222 to be turned off.

The second comparator 304 may be configured to compare the dc voltage V _rect with the negative voltage V _N to obtain a second control signal ctrl2 for controlling the second switch 224 shown in fig. 2 (S2). The second control signal ctrl2 (e.g., high or logic 1) may control the second switch 224 to be turned on when V _N≥V_rect, and the second control signal ctrl2 (e.g., low or logic 0) may control the second switch 224 to be turned off when V _N＜V_rect.

The third comparator 306 may be configured to compare the signal ground (0 level) with V _N to obtain a third control signal ctrl3 for controlling the third switch 226 shown in fig. 2 (S3). When V _N is less than or equal to 0, the third control signal ctrl3 (e.g., high or logic 1) may control the third switch 226 to be turned on, and when V _N > 0, the third control signal ctrl3 (e.g., low or logic 0) may control the third switch 226 to be turned off.

The fourth comparator 308 may be configured to compare the signal ground (0 level) with V _P to obtain a fourth control signal ctrl4 for controlling the fourth switch 228 shown in fig. 2 (S4). The fourth control signal ctrl4 (e.g., high or logic 1) may control the fourth switch 228 to turn on when V _P is less than or equal to 0, and the fourth control signal ctrl4 (e.g., low or logic 0) may control the fourth switch 228 to turn off when V _P > 0.

As shown in fig. 3, in one embodiment, the control unit 300 may also be configured to generate a conduction control signal ctrl0 that controls the switch 104 coupled to the energy storage element 106.

Referring to fig. 4 and 5, in one embodiment, the on control signal ctrl0 is high during the inversion of the voltages V _P and V _N, when the switch 104 is on, and can be controlled according to the variation period of the voltages V _P and V _N, the switch 104 starts to be on every 1/2 variation period passes, and the switch 104 is controlled to be off after a period of time.

Referring to fig. 4 and 5, in another embodiment, the turn-on control signal ctrl0 is high during the inversion of voltages V _P and V _N, when the switch 104 is turned on. For example, the switch 104 starts to turn on when V _P or V _N reaches the extreme value, and turns off when V _P or V _N rises on the rising edge, for example, when V _P or V _N rises to a preset voltage value, the on control signal ctrl0 goes low.

For example, referring to fig. 3, the control unit 300 may include a first detection device for determining that the voltage V _P or V _N is at a rising edge, and/or that the voltages V _P and V _N have not yet risen to V _rect or fallen to 0 after being flipped, according to one or more of the first control signal ctrl1, the second control signal ctrl2, the third control signal ctrl3, and/or the fourth control signal ctrl 4. For example, the first detection means may include the first D flip-flop 310 and/or the second D flip-flop 312, but the present invention is not limited thereto.

In one embodiment, the first control signal ctrl1 or the third control signal ctrl3 (e.g., shown by dashed line 342) may be coupled to the clock input of the first D flip-flop 310 as a clock input signal; accordingly, the second control signal ctrl2 corresponding to the first control signal ctrl1 or the fourth control signal ctrl4 corresponding to the third control signal ctrl3 (e.g., as indicated by the dotted line 344) may be used as the first reset signal of the first D flip-flop 310, and then the first detection signal ctrl_ VPh2l may be obtained.

Referring to fig. 4 and 5, an example of a timing diagram of the first detection signal ctrl_ VPh2l is shown. For example, as shown in fig. 4 and 5 by the dashed box 402, when a flip occurs in which the voltage V _P falls and the voltage V _N rises, the first detection signal ctrl_ VPh2l has a high level, corresponding to the voltage V _P being on the falling edge (e.g., the first control signal ctrl1 changing from 1 to 0 or the third control signal ctrl3 changing from 1 to 0) and the voltage V _N being on the rising edge. The first detection signal ctrl_ VPh l is reset to a low level until the flip change is detected again, corresponding to the voltage V _N rising to V _rect and/or V _P falling to ground level (e.g., the second control signal changing from 0 to 1 or the fourth control signal ctrl4 changing from 0 to 1).

Similarly, the second control signal ctrl2 or the fourth control signal ctrl4 (e.g., as shown by a dotted line 346) may be used as the clock input signal of the second D flip-flop 312, and the first control signal ctrl1 (e.g., as shown by a dotted line 342) corresponding to the second control signal ctrl2 or the third control signal ctrl3 corresponding to the fourth control signal ctrl4 may be used as the second reset signal of the second D flip-flop 312, so that the second detection signal ctrl_ VPl2h may be obtained.

Referring to fig. 4 and 5, an example of a timing diagram of the second detection signal ctrl_ VPl2h is shown. For example, as shown in a dashed box 404 of fig. 4, when a flip occurs in which the voltage V _N falls and the voltage V _P rises, the second detection signal ctrl_ VPl2h has a high level corresponding to the voltage V _N being on the falling edge and the voltage V _P being on the rising edge (for example, the second control signal ctrl2 changing from 1 to 0 or the fourth control signal ctrl4 changing from 1 to 0). The second detection signal ctrl_ VPl2h resets to a low level until the flip change is again detected, corresponding to the voltage V _P rising to V _rect (e.g., greater than or equal to V _rect) and/or V _N falling to zero (e.g., lower than or equal to ground).

As shown in fig. 3, the control unit 300 further includes a second detecting device for detecting whether the voltages V _P and V _N reach a preset voltage value. The second detection device may selectively compare V _P or V _N to a predetermined voltage value. In one embodiment, the second detection means comprises a fifth comparator 318. For example, the preset voltage value may be a partial voltage v_f of V _rect. In one embodiment, the voltage divider 316 may be utilized to generate the divided voltage v_f by dividing the dc voltage V _rect. For example, v_f=α·v _rect, where α is a predetermined partial pressure coefficient. The voltage division coefficient α may depend on the Q value of the inductor and the losses on the branches. For example, 0.5 < α < 1, the numerical range is only one example and not limiting of the invention.

Referring to fig. 3, the first detection signal ctrl_ VPh2l is used to control the fifth switch 320 (S5), and the second detection signal ctrl_ VPl h is used to control the sixth switch 322 (S6), so that the INP terminal of the fifth comparator 318 is connected to V _N or V _P at an appropriate timing. For example, when the first detection signal ctrl_ VPh l is high (e.g., corresponding to the voltage V _N being on a rising edge), the fifth switch 320 may be controlled to couple the voltage V _N on the rising edge to the INP terminal of the fifth comparator 318. When the second detection signal ctrl_ VPl2h is high (e.g., corresponding to voltage V _P being on a rising edge), the sixth switch 322 may be controlled to couple the voltage V _P on the rising edge to the INP terminal for the fifth comparator 318.

In one embodiment, the fifth comparator 318 may detect whether the INP terminal voltage is greater than or equal to the divided voltage v_f by comparing the voltage (V _N or V _P) to which the INP terminal is coupled with the divided voltage v_f, thereby obtaining the third detection signal off. For example, the third detection signal off has a high level when the voltage V _N or V _P is greater than or equal to the partial voltage v_f. In contrast, the third detection signal off has a low level.

Referring to fig. 3, the control unit 300 may further include a third detecting device for detecting whether V _P and V _N are in the flipped state. The control unit 300 further comprises reset control means for detecting whether V _P and V _N are in the flipped or flipped ready state and/or resetting the third detection means. In one embodiment, the third detection means comprises a third D flip-flop 332. The reset control means comprises a first or gate 330. In one embodiment, the third detection signal off may be used as the clock input signal of the third D flip-flop 332, and the reset control (ready) signal ctrl_r from the first or gate 330 may be used as the reset control signal of the third D flip-flop 332, thereby obtaining the flip-flop detection signal ctrl_on. In one embodiment, the reset control signal ctrl_r may indicate whether the voltage V _P or V _N is in a flip or in a flip ready state. For example, the reset control signal ctrl_r has a high level corresponding to the voltage V _P or V _N being greater than V _rect to indicate that the voltage V _P or V _N is in the flipped ready state, otherwise the reset control signal ctrl_r is low level to indicate that the voltage V _P or V _N is in flipping. Or the reset control signal ctrl_r has a high level corresponding to the voltage V _P or V _N being lower than zero or ground level to indicate that the voltage V _P or V _N is in the flip ready state, otherwise the reset control signal ctrl_r is low level to indicate that the voltage V _P or V _N is in the flip. In one embodiment, the first or gate 330 may be used to logically or the first control signal ctrl1 with the second control signal ctrl2, or to logically or the third control signal ctrl3 with the fourth control signal ctrl4, so as to obtain the reset control signal ctrl_r.

Referring to fig. 4 or 5, in one embodiment, if the reset control signal ctrl_r is at a high level, the flip detection signal ctrl_on is reset to a high level; if the reset control signal ctrl_r is at a low level, the inversion detection signal ctrl_on is triggered by the third detection signal off corresponding to the voltage V _P or V _N being in inversion. If the reset control signal ctrl_r is low to indicate the start of the inversion, as indicated by the dashed box 402, the third detection signal off is low when V _N or V _P has not yet risen to the preset voltage value v_f during the inversion of V _P and V _N, and the inversion detection signal ctrl_on is high, corresponding to the voltages V _P and V _N being in the fast inversion state. When V _N or V _P rises to v_so that the third detection signal off changes from low level to high level, the flip detection signal ctrl_on changes to low level, thereby indicating the end of the flip process of V _P and V _N. When the flip process of V _P and V _N ends, the reset ctrl_r goes high (e.g., one of V _N or V _P rises to V _rect and the other falls to 0) to reset the flip detection signal ctrl_on high.

Referring to fig. 3, the control unit 300 further includes a turn-on control signal generating means for obtaining a turn-on control signal ctrl0 according to the flip detection signal ctrl_on, the first detection signal ctrl_ VPh2l, and the second detection signal ctrl_ VPl2 h. As shown in fig. 3, the on control signal generating device may include a first and gate 324 for logically and-ing the flip detection signal ctrl_on and the first detection signal ctrl_ VPh2l to obtain a first logical and result; a second AND gate 326 for logically AND the flip detection signal ctrl_on with the second detection signal ctrl_ VPl2h to obtain a second logical AND result; and a second or gate 328 for logically or-ing the first and second logical and results, so that the on control signal ctrl0 for the switch 104 can be obtained, but the present invention is not limited thereto. In one embodiment, according to the flip detection signal ctrl_on, the first detection signal ctrl_ VPh2l, and the second detection signal ctrl_ VPl h, the turn-on control signal generating device may generate the turn-on control signal ctrl0 having a high level to control the switch 104 to be turned on when V _P or V _N has not risen to the preset voltage value v_f in response to V _P and V _N flip start; if V _P or V _N rises to the preset voltage value V_f, the on control signal ctrl0 goes low to turn off the switch 104 so that V _P and V _N quickly flip over during the on time of the switch 104 to maximize piezoelectric energy harvesting.

For example, as shown in fig. 4 and 5, one example of a simulated waveform of bias flip (bias flip) is schematically shown. Corresponding to detecting the zero crossing point of the equivalent current i _eq in the piezoelectric element model shown by the dashed box 110 in fig. 1 or 2 (for example, equivalent to the vibration of the piezoelectric element 110 to the maximum displacement shown by 404 or 406 in fig. 5), V _P and V _N start to flip (dashed box 402), the on control signal ctrl0 jumps from low level to high level, and can jump back to low level when V _P or V _N rises to the preset voltage value v_f during the flip, so as to control the switch 104 to be turned off, thereby realizing the fast flip of V _P and V _N. The on-off of the switch 104 is controlled by the on-control signal ctrl0 of the control unit 202, so that the P-SSHI function is realized through the inductor 106 and the switch 104 connected in series, which is shown as fast bias inversion, and the energy collection efficiency is improved.

Fig. 6 shows an example of a flow chart of a method according to an embodiment of the invention. In one embodiment, the method may be used to implement bias flip of P-SSHI.

As shown in fig. 6 and referring to fig. 1 or 2, at block 602, the switch 104 coupled to the energy storage element 106 may be controlled to conduct for a preset time at each of the 1/2 cycles V _P and V _N (the changing cycles of V _P and V _N) passing (e.g., as shown at 404 or 406 in fig. 5) so that V _P and V _N begin to invert. In one embodiment, the 1/2 cycle point may correspond to the piezoelectric element 110 deforming to a maximum point, e.g., V _P or V _N will start to fall or rise from, e.g., a maximum or minimum, i.e., will start to flip. The on preset time may be set to half the resonance period of the equivalent capacitor 114 and inductor 106 of the piezoelectric element 110, but the invention is not limited thereto, and the on preset time may be set to other times that are much smaller than the variation period of V _P and V _N, so that V _P and V _N are flipped rapidly within the switch on time to maximize piezoelectric energy collection. At decision block 604, a determination may be made as to whether the preset time has elapsed. If the conduction preset time has elapsed (e.g., corresponding to the end of the inversion), then at 606, the switch 104 of the energy storage element 106 is controlled to open to achieve biased inversion through the P-SSHI function of the energy storage element 106 and the switch 104, without oscillation, which in turn increases energy harvesting efficiency. If, on the contrary, the preset time is not reached, the flow of block 602 is continued to continue to conduct the switch 104 connected to the energy storage element 106.

Although not shown in fig. 6, in one embodiment, the method shown in fig. 6 may further include detecting voltage values of V _P and V _N, and/or generating first to fourth control signals ctrl1 to ctrl4 according to a comparison result of V _P or V _N compared with V _rect and/or a ground level, and/or controlling on or off of the first to fourth switches using the first to fourth control signals ctrl1 to ctrl4, respectively, but the present invention is not limited thereto.

Fig. 7 shows an example of a flow chart of a method according to an embodiment of the invention. In one embodiment, the method may be used to implement bias flip of P-SSHI.

As shown in fig. 7 and referring to fig. 1 or 2, at block 702, switch 104 in series with energy storage element 106 may be controlled to conduct after V _P and V _N reach an extremum. At decision block 704, it may be determined whether V _P or V _N has risen to a predetermined voltage value by detecting a rising edge of the positive voltage V _P or the negative voltage V _N of the piezoelectric element 110. For example, the preset voltage value may include a divided voltage v_f of the rectified voltage V _rect. For example, v_f=α·v _rect, where 0.5 < α < 1.

If it is determined at decision block 704 that either V _P or V _N rises to the predetermined value, flow proceeds to block 706 to control the switch 104 connected to the energy storage element 106 to open, thereby enabling the energy storage element 106 and switch 104 to implement the P-SSHI function without oscillation during the bias flip, thereby improving energy harvesting efficiency. If it is determined at decision block 706 that either V _P or V _N has not risen to the preset voltage value, flow returns to block 702 to continue to turn on the switch 104.

Although not shown in fig. 7, in one embodiment, the method shown in fig. 7 may further include detecting voltages of V _P and V _N, and/or generating first to fourth control signals ctrl1 to ctrl4 according to a comparison result of V _P or V _N compared with V _rect and/or a ground level, and/or controlling on or off of the first to fourth switches using the first to fourth control signals ctrl1 to ctrl4, respectively, but the present invention is not limited thereto.

Fig. 8 shows an example of a method according to an embodiment of the invention. In one embodiment, the method may be used to generate the turn-on control signal ctrl0 as shown in fig. 4 or 5, for example, according to V _P、V_N and/or V _rect.

As shown in fig. 8, at block 802, the piezoelectric voltage V _P or V _N may be compared to the rectified voltage V _rect or to ground level to generate the first through fourth control signals (ctrl 1 through ctrl 4) as described above.

At block 804, a rising edge of V _P or V _N and/or a flip of voltages V _P and V _N may be detected by the first through fourth control signals to obtain a first detection signal (ctrl_ VPh2 l) and/or a second detection signal (ctrl_ VPl2 h) and/or a reset control signal (ctrl_r). For example, voltages V _P and V _N flip corresponding to the rising edge of V _P or V _N. The first control signal or the third control signal and the second control signal or the fourth control signal can be logically or-ed to obtain the reset control signal. The flip detection signal may have a high level corresponding to the reset control signal that one of V _P or V _N rises to V _rect and the other falls to ground level to indicate that V _P and V _N are in a flip ready state.

In response to detecting the first and/or second detection signals indicative of the rising edge of V _P or V _N and/or the reset control signal indicative of voltages V _P and V _N ready to flip (block 804), at block 806, it is determined whether the voltage V _P or V _N at the rising edge rises to a preset voltage value by comparing the voltage V _P or V _N at the rising edge with the preset voltage value to obtain a third detection signal (off). For example, the preset voltage value may be a divided voltage (v_f) of the rectified voltage V _rect as described above. In one embodiment, the voltage at the rising edge of V _P and V _N may be selectively compared to the preset voltage value based on the first detection signal and/or the second detection signal obtained at block 804.

At block 808, it is detected whether V _P and V _N are still in the flipped state based on the third detection signal (off) and/or the flip detection signal (ctrl_on) of the reset control signal (ctrl_r). For example, if the reset control signal is low indicating that the voltage V _P or V _N is in the flipped state, and the third detection signal obtained at block 806 indicates that the voltage V _P or V _N has not yet risen to the preset voltage value, the obtained flipped detection signal may have a high level, corresponding to V _P and V _N still being in the flipped state, the flipping has not yet ended. If the third detection signal obtained at block 806 indicates that either voltage V _P or V _N has risen to the preset voltage value, the obtained flip detection signal may have a low level, at which point V _P and V _N end the fast flip process. Further, when the reset control signal is at a high level (corresponding to one of V _P or V _N rising to V _rect and the other falling to ground), the inversion detection signal may have a high level, corresponding to V _P and V _N being in an inversion ready state.

At block 810, a turn-on control signal may be generated based on the first detection signal, the second detection signal, and the flip detection signal to control turning on or off of the switch 104 shown in fig. 1 or 2. For example, the turn-on control signal may be obtained by logically ANDed the flip detection signal with the first detection signal and the second detection signal, respectively, and then logically ANDed the result of the logical ANDed. As shown in fig. 4 or 5, the switch 104 may be turned on by the on control signal after V _P and V _N reach an extreme value, and the switch 104 may be turned off when V _P or V _N rises to a preset voltage value during the flipping process.

Fig. 9 illustrates an example apparatus 900 according to an embodiment of the invention. In one embodiment, the device 900 may include various architectures and/or various computing modules and/or electronic devices, etc. of one or more integrated circuit chips and/or packages. One or more processing modules 902 may be included, as well as one or more storage modules 904 coupled to the one or more processing modules 902. In one embodiment, the one or more memory modules 904 may include various memory modules such as random access memory, dynamic random access memory, or static random access memory. In one embodiment, the one or more memory modules 904 may be used to store one or more instructions (e.g., machine-readable instructions and/or computer programs) that are readable and/or executable by the one or more processing modules 902. The one or more instructions may also be stored on a non-transitory machine-readable storage medium. The one or more instructions, in response to being executed, cause the one or more processing modules 902 to implement the control units shown in fig. 1-3, and/or perform one or more operations as described above with reference to fig. 1-8. In one embodiment, fig. 9 illustrates only one example of an apparatus 900, and is not limiting of the invention, in some embodiments, the apparatus 900 may also include one or more other modules and/or portions (not shown). In one embodiment, the various modules of the apparatus 900 may be implemented by hardware, software, firmware, and/or various combinations thereof, although the invention is not limited in this respect.

As shown in fig. 1 to 9, according to an embodiment of the present invention, since the voltage and/or the variation period of the voltage V _P、M_N is detected and the detected signal is fed back to the piezoelectric energy collection interface circuit, when V _P、V_N reaches an extreme value and/or every 1/2 variation period passes, a switch connected in series with the energy storage element of the piezoelectric element can be controlled to be turned on and turned off after a period of time, wherein the on time is far less than the variation period of the positive voltage or the negative voltage, thereby achieving the effects of preventing oscillation, realizing rapid inversion, and improving the energy collection efficiency, so as to maximize the piezoelectric energy collection. In addition, according to another embodiment of the present invention, the switching on and off of the rectifier bridge of the piezoelectric energy collection interface circuit can be controlled, so that piezoelectric or vibration energy collection can be performed to achieve the effect of reducing energy loss. According to the above aspects of the present invention, the fully integrated circuit can be utilized to implement the P-SSHI function autonomously without requiring an additional MCU to implement the control logic.

The above embodiments are merely examples of the present invention, and are not intended to limit the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An interface circuit for piezoelectric energy collection for realizing SSHI function, characterized by comprising a control unit for generating a conduction control signal for controlling conduction of a switch connected in series with an energy storage element of the piezoelectric element and controlling conduction of the switch in a period of time so that a positive electrode voltage and a negative electrode voltage of the piezoelectric element are rapidly turned over in the period of time in which the switch is conducted to thereby achieve prevention of oscillation, so as to perform maximum piezoelectric energy collection, the control unit setting a time at which the switch is conducted by depending on a variation cycle of the positive electrode voltage and the negative electrode voltage or depending on whether the positive electrode voltage or the negative electrode voltage reaches an extremum; or the switch is disconnected after the switch is conducted for a preset time; or detecting the rising edge of the positive electrode voltage or the negative electrode voltage, and when the positive electrode voltage or the negative electrode voltage rises to a preset voltage value, switching off the switch connected in series with the energy storage element to control the conduction time period; the preset voltage value is the voltage division V_f=alpha.Vrect of the voltage rectified by the interface circuit, wherein alpha is a preset voltage division coefficient, and 0.5 < alpha < 1; the preset time corresponds to half of a resonance period of equivalent capacitance of the energy storage element and the piezoelectric element or is set to be far smaller than a change period of the positive electrode voltage and the negative electrode voltage.

2. Interface circuit according to claim 1, characterized in that the control unit comprises comparison means for comparing a positive voltage and/or a negative voltage with the voltage rectified by the interface circuit and with a ground level to generate one or more of the first to fourth control signals, respectively; and/or first detection means for judging whether the positive electrode voltage or the negative electrode voltage is at a rising edge by one or more of the first to fourth control signals to give a first detection signal and a second detection signal; the second detection device is used for comparing the positive electrode voltage or the negative electrode voltage at the rising edge with a preset voltage value to detect whether the positive electrode voltage or the negative electrode voltage rises to the preset voltage value or not so as to obtain a third detection signal; and/or third detection means for determining whether the inversion of the positive electrode voltage and the negative electrode voltage is ended by the third detection signal to obtain an inversion detection signal; and/or a conduction control signal generating device for generating a conduction control signal for controlling the switch connected in series with the energy storage element according to the first detection signal, the second detection signal and the inversion detection signal.

3. Interface circuit according to claim 1 or 2, characterized in that the control unit further comprises first to fourth comparators for comparing the positive voltage and/or the negative voltage with the voltage rectified by the interface circuit and with a ground level for generating first to fourth control signals, respectively; and/or first and second D flip-flops for determining whether the positive electrode voltage or the negative electrode voltage is at a rising edge by one or more of the first to fourth control signals to give a first detection signal and a second detection signal, respectively; a fifth comparator for comparing the positive voltage or the negative voltage at the rising edge with a preset voltage value to detect whether the positive voltage or the negative voltage rises to the preset voltage value or not so as to give a third detection signal; and/or a first or gate for generating a reset control signal by logically or-ing the first and second control signals or by logically or-ing the third and fourth control signals; and/or a third D trigger, which is used for determining the end of the turning of the positive electrode voltage and the negative electrode voltage through the third detection signal and the reset signal so as to give a turning detection signal; and/or a first AND gate for logically AND the flip detection signal with the first detection signal; and/or a second AND gate for logically AND the flip detection signal with the second detection signal; and/or a second or gate for logically or-ing the result of the first and gate with the result of the second and gate to generate a conduction control signal for controlling the switch in series with the energy storage element.

4. The interface circuit of claim 2, further comprising a switching circuit coupled to the control unit, the switching circuit including first to fourth switches controlled to turn on or off by the first to fourth control signals, respectively; and/or any one of the first to fourth switches is a diode; and/or any one of the first to fourth switches comprises a diode, a selective switching tube; and/or the selective switch tube comprises a triode, a transistor and a metal oxide semiconductor tube; and/or the first to fourth switches are used to construct a full-wave rectifier bridge that converts the alternating voltage of the positive and negative voltages to a direct voltage.

5. Interface circuit according to claim 2, characterized in that the control unit further comprises a first comparator for comparing the rectified voltage with the positive voltage to obtain a first control signal, and/or that the first control signal controls the first switch to be turned on at V _P≥V_rect and the first control signal controls the first switch to be turned off at V _P＜V_rect; and/or a second comparator for comparing the rectified voltage with the negative voltage to obtain a second control signal, and/or the second control signal controls the second switch to be turned on when V _N≥V_rect and the second control signal controls the second switch to be turned off when V _N＜V_rect; a third comparator for comparing the ground level with the negative voltage to obtain a third control signal, and/or when V _N is less than or equal to 0, the third control signal controls the third switch to be turned on, and when V _N is more than 0, the third control signal controls the third switch to be turned off; and/or a fourth comparator for comparing the ground level with the positive voltage to obtain a fourth control signal, and/or when V _P is less than or equal to 0, the fourth control signal controls the fourth switch to be turned on, and when V _P is more than 0, the fourth control signal controls the fourth switch to be turned off, wherein V _P is the positive voltage, V _N is the negative voltage, and V _rect is the rectified voltage.

6. A control unit for an interface circuit for piezoelectric energy collection, for realizing piezoelectric energy collection of SSHI function, comprising a conduction control signal generating means for generating a conduction control signal for controlling conduction of a switch connected in series with an energy storage element so that a positive electrode voltage-negative electrode voltage of the piezoelectric element is rapidly turned over during a conduction time of the switch to realize bias turning and piezoelectric energy collection, the conduction control signal generating means for setting the conduction control signal for turning on the switch every time a half cycle time point of the positive electrode voltage or the negative electrode voltage corresponding to a maximum point of deformation of the piezoelectric element and turning off after the conduction time according to a variation cycle of the positive electrode voltage and the negative electrode voltage; or detecting the extreme value of the positive voltage or the negative voltage, and detecting that the positive voltage or the negative voltage rises to a preset voltage value from the extreme value at the rising edge so as to control the on time to generate the on control signal; the preset voltage value is the voltage division V_f=alpha.Vrect of the rectified voltage of the interface circuit, wherein alpha is a preset voltage division coefficient, and 0.5 < alpha < 1; the extreme value corresponds to a critical point at which the positive electrode voltage or the negative electrode voltage starts to turn over; the on time corresponds to half of a resonance period of the equivalent capacitance of the energy storage element and the piezoelectric element or corresponds to a time when the positive voltage or the negative voltage rises from the lowest value of the positive voltage or the negative voltage to the preset voltage value.

7. The control unit according to claim 6, further comprising comparing means for comparing the positive voltage and/or the negative voltage with the voltage rectified by the interface circuit and with a ground level to generate one or more of the first to fourth control signals, respectively; and/or first detection means for detecting that the positive electrode voltage or the negative electrode voltage is at a rising edge by one or more of the first to fourth control signals to obtain a first detection signal and a second detection signal; the second detection device is used for comparing the positive electrode voltage or the negative electrode voltage at the rising edge with a preset voltage value to detect whether the positive electrode voltage or the negative electrode voltage rises to the preset voltage value or not so as to obtain a third detection signal; and/or third detection means for determining the end of the inversion of the positive electrode voltage and the negative electrode voltage by the third detection signal to give an inversion detection signal; and/or the conduction control signal generating device is used for generating a conduction control signal for controlling the switch connected with the energy storage element in series according to the first detection signal, the second detection signal and the turnover detection signal.

8. The control unit according to claim 7, further comprising first to fourth comparators for comparing the positive voltage and/or the negative voltage with the voltage rectified by the interface circuit and with a ground level to generate first to fourth control signals, respectively; and/or first and second D flip-flops for detecting whether a positive electrode voltage or a negative electrode voltage is at a rising edge by one or more of the first to fourth control signals to obtain a first detection signal and a second detection signal, respectively; a fifth comparator for comparing the positive voltage or the negative voltage at the rising edge with a preset voltage value to detect whether the positive voltage or the negative voltage rises to the preset voltage value or not, so as to obtain a third detection signal; and/or a third D trigger for determining the end of the positive voltage and the negative voltage inversion by the third detection signal to give an inversion detection signal; and/or a first AND gate for logically AND the flip detection signal with the first detection signal; and/or a second AND gate for logically AND the flip detection signal with the second detection signal; and/or a second or gate for logically or-ing the result of the first and second and gate to generate a conduction control signal for controlling the switch of the energy storage element in series.

9. The control unit of claim 7, wherein first to fourth switches of the interface circuit are controlled to be turned on or off by the first to fourth control signals, respectively; and/or any one of the first to fourth switches is a diode; and/or any one of the first to fourth switches comprises a diode, a selective switching tube; and/or the selective switch tube comprises a triode, a transistor and a metal oxide semiconductor tube; and/or the first to fourth switches are used to construct a full-wave rectifier bridge that converts the alternating voltage of the positive and negative voltages to a direct voltage.

10. The control unit of claim 7, wherein the control unit is further configured to compare the rectified voltage with the positive voltage to obtain a first control signal, and/or wherein the first control signal controls the first switch to be turned on at V _P≥V_rect and the first control signal controls the first switch to be turned off at V _P＜V_rect; and/or a second comparator for comparing the rectified voltage with the negative voltage to obtain a second control signal, and/or the second control signal controls the second switch to be turned on when V _N≥V_rect and the second control signal controls the second switch to be turned off when V _N＜V_rect; a third comparator for comparing the ground level with the negative voltage to obtain a third control signal, and/or when V _N is less than or equal to 0, the third control signal controls the third switch to be turned on, and when V _N is more than 0, the third control signal controls the third switch to be turned off; and/or a fourth comparator for comparing the ground level with the positive voltage to obtain a fourth control signal, and/or when V _P is less than or equal to 0, the fourth control signal controls the fourth switch to be turned on, and when V _P is more than 0, the fourth control signal controls the fourth switch to be turned off, wherein V _P is the positive voltage, V _N is the negative voltage, and V _rect is the rectified voltage.

11. A method for piezoelectric energy harvesting for implementing SSHI functionality, comprising generating a conduction control signal for controlling a switch in series with an energy storage element of the piezoelectric element to conduct at a time corresponding to a deformation of the piezoelectric element to a maximum point and controlling a conduction time of the switch so that a positive voltage and a negative voltage of the piezoelectric element rapidly flip over within the switch conduction time to maximize piezoelectric energy harvesting, the time corresponding to a time per half cycle point of a change in the positive voltage or the negative voltage or the positive voltage or the negative voltage reaching an extremum, the method further comprising controlling the conduction time to be substantially smaller than a period of change in the positive voltage and the negative voltage of the piezoelectric element; or detecting the rising edge of the positive electrode voltage or the negative electrode voltage of the piezoelectric element to determine whether the positive electrode voltage or the negative electrode voltage rises to a preset voltage value so as to open the switch, wherein the preset voltage value is the partial pressure V_f=alpha-Vrect of the voltage obtained by rectifying the positive electrode voltage and the negative electrode voltage, alpha is a preset partial pressure coefficient, and 0.5 < alpha < 1.

12. The method of claim 11, further comprising determining whether a conduction time at the switch has ended, controlling the switch of the series of energy storage elements to open in response to the conduction time having ended, and/or maintaining the switch of the series of energy storage elements to open in response to the conduction time not ending; and/or judging whether the positive voltage or the negative voltage rises to the preset voltage value after the switch is conducted, and responding to the fact that the positive voltage or the negative voltage does not rise to the preset voltage value, keeping the switch of the energy storage element conducted; and/or controlling a switch connected with the energy storage element to be disconnected in response to the positive electrode voltage or the negative electrode voltage rising to the preset voltage value.

13. The method of claim 12, further comprising generating first through fourth control signals by comparing the positive voltage or the negative voltage with the rectified voltage and with a ground level; and/or controlling on or off of first to fourth switches of the switching circuit for piezoelectric energy collection using the first to fourth control signals, respectively; and/or generating first to fourth control signals and/or a conduction control signal for controlling the conduction or disconnection of the switches of the series connection of energy storage elements by processing the positive voltage, the negative voltage and/or the rectified voltage.

14. The piezoelectric energy collection method for realizing the SSHI function is characterized by comprising the steps of detecting whether the positive electrode voltage or the negative electrode voltage rises to a preset voltage value when the positive electrode voltage and the negative electrode voltage of a piezoelectric element are turned over; or in response to detecting that the positive voltage or the negative voltage rises to the preset voltage value, generating a conduction control signal for switching off a switch which connects the energy storage elements of the piezoelectric elements in series, wherein the conduction control signal is also used for controlling the switch to be switched on at the moment corresponding to the maximum deformation of the piezoelectric elements and controlling the switch to be switched off when the positive voltage or the negative voltage rises to the preset voltage value after being switched on so as to realize the rapid overturn of the positive voltage and the negative voltage; the preset voltage value may include a partial voltage v_f=α·vrect for the voltage rectified by the switching circuit of the piezoelectric element, where α is a predetermined partial voltage coefficient, 0.5 < α < 1.

15. The method of claim 14, further comprising comparing the rectified voltage with a positive voltage or a negative voltage and with a ground level to generate first through fourth control signals; and/or detecting rising edges of the positive electrode voltage or the negative electrode voltage by the first to fourth control signals to obtain a first detection signal and a second detection signal, respectively; and/or selectively comparing the negative voltage or the positive voltage with the preset voltage value according to the first detection signal and the second detection signal to generate a third detection signal; and/or detecting whether the positive voltage and the negative voltage are in a flipping ready state by judging whether one of the positive voltage and the negative voltage is greater than the rectified voltage or whether one of the positive voltage and the negative voltage is less than a ground level to generate a reset control signal; and/or generating a flip detection signal according to the third detection signal and the reset control signal.

16. The method of claim 15, further comprising, in response to detecting that the positive voltage or the negative voltage does not rise to the preset voltage value, causing the rollover detection signal to have a first level to indicate that rollover has not ended; and/or in response to the positive voltage or the negative voltage rising to the preset voltage value, enabling the inversion detection signal to have a second level lower than the first level; and/or in response to detecting that one of the positive voltage and the negative voltage is greater than the rectified voltage or one of the positive voltage and the negative voltage is less than the ground level, the inversion detection signal is made to have a first level corresponding to the positive voltage and the negative voltage being in an inversion ready state; and/or generating the on control signal according to the first detection signal, the second detection signal and the flip detection signal; and/or the inversion detection signal is logically and-ed with the first detection signal and the second detection signal respectively, and the result of the logical and is logically or-ed to obtain the conduction control signal.

17. A non-transitory machine-readable storage medium comprising one or more instructions that in response to being executed result in one or more processing modules performing one or more steps of the method of any of claims 11-16.

18. A control apparatus characterized by comprising:

one or more processing modules;

One or more storage modules coupled with the one or more processing modules, the storage modules to store one or more instructions that, in response to being executed, cause the one or more processing modules to perform one or more steps of the method of any of claims 11-16.