WO2006047926A1

WO2006047926A1 - The method of piezoelectric generator of generating electricity using the vehicle vibration and the system

Info

Publication number: WO2006047926A1
Application number: PCT/CN2005/001670
Authority: WO
Inventors: Binggang Cao; He Zuo; Longyun Kang; Jiarang Lin
Original assignee: Xi'an Jiaotong University
Priority date: 2004-11-08
Filing date: 2005-10-12
Publication date: 2006-05-11
Also published as: CN1292930C; CN1603155A

Abstract

The method of piezoelectric generator of generating electricity using the vehicle vibration and the system, wherein the piezoelectric device is installed in the suspension, which generates electricity using the vibration and storages the electricity as power supply and uses said electricity power. The system include: an electricity transform device for adjusting and transforming power generated by piezoelectric device, and using the power to a storage device r the last electrical load; at least a storage device and the last electrical load. The piezoelectric device is connected to the electricity transform device. The invention supplies a new power resource for the vehicle, in particular for the electrical vehicle and the hybrid vehicle. Because the power can be used directly, the continuous drive distant is increased effectually. The invention can function as a half-initiative damping with the proper control method.

Description

Automobile vibration energy piezoelectric power generation method and system thereof

Technical field

The invention relates to a method and a system for vehicle on-board power generation, in particular to a method and system for a vehicle vibration energy piezoelectric power generation. Background technique

The working principle of piezoelectric power supplies is based on the positive piezoelectric effect, and piezoelectric materials are their core working substances.

In the late 1960s, the Shanghai Institute of Ceramics of the Chinese Academy of Sciences and the Shanghai Precision Medical Equipment Factory jointly studied the power supply of the portable X-ray machine, and successfully obtained the DC high voltage of L = 60kV, I„^3mA.

U.S. Patent No. 4,504,761 issued to Charles G. Triplett entitled "Piezoelectric Generator Mounted on a Vehicle", which discloses a piezoelectric generator disposed on a tire of a vehicle, which utilizes application to the tire during rotation of the wheel Pressure produces electrical energy.

The Chinese invention patent CN 1202014A awarded to Jindong Bureau is entitled "Piezoelectric Generator with Piezoelectric Element Connected to Vibration Source and Its Manufacturing Method", which discloses a piezoelectric generator that generates electricity using mechanical vibration energy of a vehicle engine. . The invention includes a piezoelectric element and circuitry for storing electrical energy generated by the piezoelectric element. Each of the piezoelectric elements has a supporting member of a piezoelectric film and a piezoelectric film. The remaining pressure is applied to the support member to bend the piezoelectric element upward. Set the DC/AC converter to convert the DC power generated by the piezoelectric element into AC power, set the transformer and diode to prevent discharge from the battery.

The above examples show that it is feasible to fabricate various types of power sources using the positive piezoelectric effect of piezoelectric materials, and it is particularly suitable for power supplies of various mobile devices. The internal impedance of this power supply is capacitive. Through the conversion of the piezoelectric effect, even under static and quasi-static conditions, it can convert the energy of K ² . W _tt (K is the electromechanical coupling coefficient, K ² is the measurement of electromechanical The ability to convert energy). At present, a variety of piezoelectric materials with K≥0.7 have been successfully developed, and industrialization has been completed. The piezoelectric coefficients d ₃₃ and g _{M are} high, the mechanical strength is high, and the performance is stable after repeated pressurization. The dielectric constant Larger materials can be used as an ideal power generating work substance.

The traditional suspension system of the car is a passive suspension system, which uses two basic components, a spring and a damper. In order to pursue good ride comfort and good steering stability, if the conventional suspension using the fixed stiffness spring and the fixed damping damper has not been satisfied, a variety of automotive suspension systems using electronic technology have been developed. Its The active suspension technology is superior in performance due to the use of air pressure or oil pressure to control the force between the body and the axle, but requires greater energy consumption. The semi-active suspension technology proposed later adopts an adjustable spring or an adjustable damper to form a suspension, and according to the speed response of the sprung mass, the feedback signal, according to a certain control law, adjusts the stiffness of the adjustable spring or is adjustable. Damping force of the damper. Compared with the active suspension, the semi-active suspension control system consumes a small amount of energy and has a low cost, and is widely used commercially. Semi-active suspension technology is mainly implemented by hydraulic or electromagnetic means.

Toyota Motor Corporation of Japan has developed a Piezoelectric Electronic Control Suspension System ( _TEMS ) for passenger cars, a semi-active suspension system that can change the hydraulic damping force. In the damper of the system, a road surface sensor and a piezoelectric actuator made of piezoelectric ceramics are mounted. The piezoelectric road surface sensor in the system converts the vibration signal caused by the uneven road surface into an electric signal and sends it to the microprocessor. The microprocessor processes the signal, and controls the piezoelectric actuator to generate the expansion and contraction according to the control strategy. Deformation, the piezoelectric actuator further drives the wide core of the damper switching valve to generate displacement, and changes the damping force of the damper, thereby achieving semi-active damping control of the suspension system.

Since piezoelectric materials are both dielectric and elastomer, have positive and negative piezoelectric effects and general elastomer properties, they have both electrical and mechanical properties, and their electrical and mechanical behaviors are coupled to each other. By utilizing this electromechanical coupling property of the piezoelectric material, the piezoelectric element is connected in parallel with a circuit composed of electrical components including a resistive component, a capacitive component, an inductive component, and a switching device to form a complete piezoelectric damping system. By selecting different circuit forms in parallel with the piezoelectric elements, the combination of different electrical components and the size of the parameters, different controllable piezoelectric damping forms can be designed to passively, semi-actively and actively-passively hybridize the vibration of the structural system. Suppression and control.

For example, a technique called piezoelectric viscous damping uses a piezoelectric damper system in which a piezoelectric element and a resistor are connected in parallel, and the structure is damped by Joule heat dissipation energy.

Another example is a piezoelectric damping system in which a piezoelectric element and a capacitor are connected in parallel, which can change the effective rigidity of the piezoelectric element. With this principle, a piezoelectric damping vibration damping system having the properties of a mechanical dynamic vibration absorber can be developed.

Another example is a conversion type semi-active piezoelectric damping system formed by connecting a piezoelectric element and a switching element in parallel. By switching the switching element to open and close, a large change in equivalent stiffness can be achieved, thereby controlling the vibration energy in the structural system. Flow direction.

Piezoelectric damping vibration damping technology has been applied in several sports articles. For example, the designer of K2 Company of the United States inserts piezoelectric material into the sled. When the sled is deformed by vibration, the piezoelectric material is also deformed to convert the vibration energy into electric energy; and the resistor and the piezoelectric material are used in parallel to form a pressure. The resistor system dissipates this energy in the form of Joule heat. Summary of the invention

SUMMARY OF THE INVENTION An object of the present invention is to provide a method and system for piezoelectric vibration energy generation of a vehicle, which is placed in a suspension system of a vehicle, generates electrical energy using vibration energy, and is stored and utilized as a power supply. The method and system for automobile vibration energy piezoelectric power generation proposed by the present invention is a novel power generation method and system for collecting dissipated energy, and provides a new energy source for automobiles. This is especially important for electric vehicles and hybrid vehicles, which can effectively increase the driving range and have significant economic and social value.

Still another object of the present invention is to provide a semi-active damping effect in the process of piezoelectric power generation using vibration energy by using an appropriate control method.

In order to achieve the above object, the present invention provides a method for piezoelectric power generation using automobile vibration energy, which is placed in a suspension system of a vehicle, converts vibration energy of the automobile into electrical energy, and stores or utilizes it as a power supply; The method includes the following steps:

Adding at least one piezoelectric device to the vehicle suspension system for receiving vibration energy of the vehicle suspension, the piezoelectric material in the piezoelectric device as a working medium, and using the positive piezoelectric effect to convert the vibration energy into electrical energy b. sending electrical energy generated by the piezoelectric device to the power conversion device, wherein the electrical energy is adjusted and transformed by the power conversion device;

c Receiving, by the energy storage device or the electrical load ultimately used, the electrical energy adjusted and transformed by the power conversion device and storing or utilizing the electrical energy.

The method of the present invention also has the feature that the power conversion device includes a control module and a power module, and the control module issues an instruction, and the power module receives and executes the instruction to control the generation, storage, and utilization of the electrical energy.

When the power converted and converted by the power conversion device is received by the energy storage device, the power conversion device controls the charging voltage and current of the energy storage device.

When the power converted and converted by the power conversion device is received by the final electrical load, the power conversion device controls the supply voltage and current of the final electrical load.

The adjustment and transformation of the electrical energy by the power conversion device further includes the following steps:

1) The rectification process changes the alternating current generated by the piezoelectric material into direct current;

2) The DC/DC conversion process performs voltage and current conversion on the DC power generated in step 1).

The power conversion device includes a control module with a controller as a core, and a sensor for detecting body motion is installed, and the controller executes a control strategy to perform semi-active vibration control on the vibration of the vehicle while generating power by using the vibration energy of the vehicle. Achieve significant damping effects. The invention also provides a vibration energy piezoelectric generating system for an automobile which realizes the above method, characterized in that the system comprises:

At least one piezoelectric device disposed in the suspension system of the vehicle, the pressure device being coupled in series with a spring of the vehicle suspension system for converting vibrational energy into electrical energy;

The power conversion device is composed of a power module for adjusting and converting electrical energy generated by the piezoelectric device, and the electric energy is used for the energy storage device or the final electrical load; the control module passes the power component of the power module Controlling, converting vibrational energy into electrical energy, and utilizing the electrical load stored or ultimately used by the energy storage device;

The energy storage device or the final electrical load is used to store and utilize the electrical energy adjusted by the power conversion device; the piezoelectric device is coupled to the power conversion device, and the power conversion device is coupled to the energy storage device or the final electrical load, respectively.

The above system is further characterized in that the piezoelectric device comprises a lower piston rod, an upper piston, a hydraulic cylinder and a piezoelectric element; one end of the lower piston rod and the upper piston are placed in the hydraulic cylinder with a liquid filled therebetween; the lower piston rod Connected to the damping spring of the suspension system, the damping spring transmits the force formed by the mass vibration of the vehicle bottom to the lower piston rod, and is transmitted to the upper piston through the liquid pressure, and the piezoelectric element is placed between the upper piston and the vehicle body;

The piezoelectric element employs a piezoelectric stack in which a plurality of piezoelectric sheets are connected in parallel.

The piezoelectric element is a piezoelectric ceramic or a ferroelectric piezoelectric material or a piezoelectric composite material.

The power module of the power conversion device includes a full bridge rectifier device and a DC/DC converter, wherein the full bridge rectifier device is connected to the power output terminal of the piezoelectric element for converting the alternating current generated by the piezoelectric element into direct current; The DC converter is coupled to the full bridge rectifier to adjust the voltage and current output by the full bridge rectifier; the power switching device in the DC/DC converter performs the command communicated by the control signal.

The control module of the power conversion device includes a sensor, a filter circuit, a controller, and an opto-isolation circuit. The sensor is disposed on the power module of the piezoelectric device and the power conversion device, and is used to obtain a signal required by the microprocessor; the controller is connected to the sensor through the filter circuit, obtains a signal obtained by the sensor, and outputs a control signal; The photoelectric isolation circuit is sent to the control end of the power switching device of the power module.

Compared with the prior art, the present invention has the following advantages:

1) Provide a new source of energy for vehicles, and utilize the vibration energy of vehicles that have not been utilized in the past, especially for electric vehicles and hybrid vehicles to increase the driving range;

2) Piezoelectric power generation, as a medium power generation method, has a simple structure and fast response, and is particularly suitable for an alternating power drive mode. 3) Since the piezoelectric material has a high energy density, the piezoelectric device is small in size and light in weight, and is easy to install and modify the existing suspension system;

4) The system of the present invention is widely used in automobiles, electric vehicles, hybrid vehicles, and various special vehicles and military vehicles.

5) In the process of piezoelectric power generation using vibration energy, the appropriate control method can be used to make the system play a semi-active vibration reduction function at the same time. Unlike the piezoelectric TEMS system introduced as background art, the present invention does not achieve vibration control by changing the hydraulic damping force of the damper, but achieves semi-active vibration control by changing the effective load of the piezoelectric element and adjusting its piezoelectric damping. . DRAWINGS

The details, embodiments, and effects of the vehicle orbital vibration energy piezoelectric generating method and system of the present invention will be more apparent from the following detailed description of embodiments with reference to the accompanying drawings, wherein:

1 is a block diagram showing the structure of a piezoelectric vibration energy piezoelectric generating system of the present invention;

Figure 2 is a schematic view of a piezoelectric device according to a first embodiment of the present invention;

3 is a circuit schematic diagram of a power module in the power conversion device of the first embodiment;

Figure 4 is a control schematic diagram of the power conversion device of the first embodiment;

Fig. 5 is a circuit schematic diagram of a power module in the power conversion device of the second embodiment. detailed description

Specific embodiments for implementing the above-described technical solution of the present invention will be described in detail below with reference to Figs. As shown in FIG. 2, the technical idea of the first embodiment of the present invention is: inserting at least one piezoelectric device between the spring of the vehicle suspension system and the vehicle body, the device being connected in series with the spring; FIG. 2 shows the first implementation The structure of the piezoelectric device in the example. The voltage generated by the piezoelectric material under compressive stress and the primary energy storage formula:

The technical route of the first embodiment is:

U=Q/C (1)

U in the formula represents the voltage generated by the piezoelectric material,

W represents the electrostatic energy stored in the piezoelectric material,

Q represents the amount of electricity generated by the piezoelectric material,

C represents the electrostatic capacitance of the piezoelectric material. From the above equations (1) and (2), it can be seen that the capacity of a pressurized energy storage is proportional to the square of the voltage after the piezoelectric material is pressed. The formula for generating voltage from piezoelectric materials is:

U= e„— (3)

S ³³ IW

Where & ³ is the piezoelectric longitudinal voltage constant, ¹ , and ^ are the length, width and thickness of the piezoelectric material, respectively, and F is the force applied to the piezoelectric material. It can be seen from the formula (3) that the voltage generated by the piezoelectric material by the stress is proportional to the force F it receives. In order to improve the piezoelectric conversion capability, a piezoelectric device as shown in Fig. 2 is used to increase the compressive stress applied to the piezoelectric material.

The device consists of a lower piston rod 4, an upper piston 2, a cylinder block 3 and a piezoelectric stack 1. One end of the lower piston rod 4 and the upper piston 2 are placed in the cylinder block 3 with hydraulic oil filled therebetween. The hydraulic cylinder block 3 and the piezoelectric stack 1 are fixedly connected to the vehicle body, respectively. The hydraulic cylinder spring 5 transmits the force formed by the unsprung mass vibration to the lower piston rod 4. The lower piston rod 4 moves in the cylinder block 3 to generate a pressure change, and the pressure change is transmitted to the upper piston 2 by the oil. The upper piston 2 directly presses the piezoelectric stack 1 to generate a new strain on the piezoelectric stack 1. Since the effective area of the lower piston is much smaller than the effective area of the upper piston, the change in the compressive stress of the piezoelectric stack is amplified in proportion to the change in the stress of the piston rod. According to the principle of positive piezoelectric effect, a charge is generated on the surface of the piezoelectric material, thereby forming the potential in the formula (1). From equation (3), this voltage is proportional to the thickness t of the piezoelectric material. In order to reduce this voltage, a piezoelectric stack formed by connecting a plurality of piezoelectric sheets in parallel is employed. This design can ensure that the working substance can be supplied with a sufficient volume, and the voltage generated by the piezoelectric material is not too high, so that the power conversion device can convert and recover the electric energy. The piezoelectric stack is made of piezoelectric ceramic material PZT, and its electromechanical coupling coefficient is _33. 7-0. 92, which has a high conversion efficiency of 3⁄4 according to the selected material type.

The adjustment and transformation of the electric energy by the power conversion device in this embodiment includes the following steps:

The rectification process converts the alternating current generated by the piezoelectric material into direct current; _; . .

The DC/DC conversion process performs voltage and current conversion on the direct current generated by the rectification process.

During the voltage transformation process, when the voltage generated by the piezoelectric material is too high, the voltage reduction process is performed before the rectification process to lower the voltage to a voltage range that the rectifying element can withstand.

The power conversion device includes a power module and a control module.

Fig. 3 is a circuit diagram showing the power module of the power conversion device in the first embodiment. The circuit consists of a rectifier and a DC/DC converter. The input of the rectifier is connected to the power output terminal of the piezoelectric element. The rectifier uses a full-bridge rectifier circuit consisting of four diodes 1^, D ₂ , and 3⁄4. The input of the rectifier is connected to the power output terminal of the piezoelectric element. The input of the DC/DC converter is connected to the output of the full bridge rectifier. The DC/DC converter is composed of the inductor C, the power switching device and the freewheeling diode D ₅ , which realizes the chopper mode. Working buck circuit. The input end of the DC/DC converter is connected to the output and end of the full bridge rectifier. The power switching device adopts IGBT IPM intelligent power module, and the module contains the necessary driving and protection circuits for the IGBT.

Fig. 4 is a diagram showing the control principle of the power conversion device in the first embodiment. The control module is composed of a current sensor, a voltage sensor, a filter circuit, a microprocessor, and an opto-isolation circuit. The microprocessor in this example uses TI's DSP chip TMS320LF2407. The voltage sensor uses a current-mode voltage sensor, and the current sensor uses a current-type current sensor. The current and voltage sensors are used to collect the voltage and current signals at the output of the DC/DC converter, which are processed by the filter circuit and sent to the A/D port of the DSP for data acquisition. After the acquisition result is processed by the DSP, the control signal is output in the form of P Li. The PWM signal is sent to the control terminal of the intelligent power module IPM via the opto-isolation circuit, to the power tube! The switch state of ^ is controlled. The signal acquisition and control frequency is l-2kHz; the PWM modulation frequency range is 10kHz-20kHz. The filter uses a typical filter circuit constructed by an operational amplifier, and the optical isolation circuit is implemented by a photocoupler. The various levels required by the control module are provided by the on-board battery via a conventional DC/DC switching power supply.

In the first embodiment, the power conversion device charges the energy storage device, and the energy storage device is a lead-acid battery. The working principle of this embodiment is:

During the operation of the automobile, the piezoelectric device is constantly subjected to varying stress due to the vibration. Through the amplification of the hydraulic cylinder in the piezoelectric device, several tons of stress are applied to the piezoelectric element in the piezoelectric device, and charges and voltages are generated at the two poles of the piezoelectric element. According to the design, the maximum open circuit voltage is limited to 500V. the following. When the absolute value of the voltage is higher than the voltage of the capacitor C on the right side of the rectifier, the piezoelectric element charges the capacitor C, otherwise the piezoelectric element is open. In the power conversion device, the control module adjusts the duty ratio of the P-signal by sampling the sensor signal. When the duty ratio increases, the power tube conduction time increases, that is, when the charging time increases, the terminal voltage of the capacitor C decreases, and the conduction voltage of the piezoelectric element to charge the capacitor C decreases; when the duty ratio decreases, the power tube guide The on-time is reduced, that is, when the charging time is decreased, the terminal voltage of the capacitor C rises, and the conduction voltage at which the piezoelectric element charges the capacitor C rises. Through the PI control algorithm, the charging voltage across the battery can be maintained at a set value, which can be set by experiment or adaptive algorithm. The principle of setting this value is to convert more vibrational energy into electrical energy. In the power tube! When disconnected, the inductor LQD ₅ can form a freewheeling circuit with the battery to continue charging the battery. The battery charging voltage and the charging current are detected by the sensor. When the battery is full, the controller stops charging the battery.

The second embodiment will be described below with reference to FIG. 5 to illustrate that the system performs semi-active control of the vibration of the vehicle body while realizing vibration energy power generation. The second embodiment is different from the first embodiment in that the power module of the power conversion device employs the schematic diagram shown in FIG. 5, and the body motion is mounted on the cylinder block 3 adjacent to the piezoelectric stack 1 in the piezoelectric device. Speed piezoelectric sensor, using both piezoelectric power generation and semi-active vibration control slightly.

Fig. 5 is a circuit diagram showing the power conversion device in the second embodiment. It differs from Figure 3 in that an IGBT IPM intelligent power module K ₂ controlled by a DSP chip is added, which is placed between the positive output of the full bridge rectifier circuit and the positive terminal of capacitor C.

The following is an analysis of how the circuit works. The control system of the circuit determines the speed of movement of the vehicle body based on the speed sensor signal. When the speed is upward, the controller gives a control signal to make the power device Κ, turn off, Κ ₂ turn on, and when the absolute value of the voltage generated by the piezoelectric element is also higher than the voltage across the capacitor C, the rectifier is turned on. The equivalent stiffness of the piezoelectric element is reduced, the upward movement of the body is slowed down, and the piezoelectric element charges the capacitor C. When the speed is downward, the controller gives a control signal to disconnect the power device Κ ₂ , the piezoelectric element, etc. The effective stiffness increases, suppressing the downward movement of the body, and the deformation of the piezoelectric element can be stored by mechanical stiffness and piezoelectric capacitance, at the same time! ^ by? The wave control, according to a certain duty cycle, capacitor C charges the battery. By right! ^The adjustment of the duty cycle allows the battery to obtain a reasonable charging voltage and charging time. As can be seen from the above discussion, the charging process of the capacitor C and the charging process of the battery alternate in time. The charging process of the capacitor C corresponds to the upward movement process of the vehicle body, and the charging process of the battery corresponds to the downward movement process of the vehicle body. At the same time, since the voltage generated by the piezoelectric element is much higher than the voltage of the battery, the dead zone of the entire system is small, ensuring that the system has high power generation and vibration damping efficiency.

Although the piezoelectric vibration energy conversion system of the present embodiment has been shown and described, the piezoelectric device is connected in series with the spring of the vehicle suspension system for converting vibration energy into electrical energy, but it should be understood that the piezoelectric effect is utilized. For the recovery of energy, the mounting of the piezoelectric device may not be limited to being connected in series with the spring. The piezoelectric device can also be mounted at other locations in the suspension system and connected to the suspension system or its components in series or in parallel. .

In addition, although the piezoelectric vibration energy piezoelectric power generation system has been discussed with reference to the above two specific embodiments, it should be understood that the structural details of the automotive vibration energy piezoelectric power generation system and the configuration of the components and components are not limited to those in the embodiment. The various changes and modifications can be made without departing from the principles of the invention.

For example, the piezoelectric element may be a piezoelectric ceramic or a ferroelectric piezoelectric material or a piezoelectric composite material.

For example, the piezoelectric device can use various well-known mechanisms, including mechanical, hydraulic, pneumatic, micro-electromechanical mechanisms, and various combinations thereof, to improve the vibration energy conversion of the piezoelectric element as the core working substance. The ability to power.

For example, the power module of the power converter includes a rectifier, a DC/DC converter and associated interface circuitry and the necessary transformers.

For example, power devices for power conversion devices employ a wide variety of widely used devices including, but not limited to, power crystals. Body tube GTR, metal-oxide-semiconductor type field effect transistor MOSFET, insulated gate bipolar transistor IGBT, and gate turn-off thyristor GT0.

For example, the controller uses an analog controller, a digital controller, and an analog-digital hybrid controller. The analog controller includes an analog controller composed of discrete components or a controller composed of a programmable analog device. The digital controller includes a microprocessor and a single-chip microcomputer. One of DSP, CPLD, and FPGA;

For example, the sensor uses a voltage sensor or a current sensor or a mechanical sensor.

For example, energy storage devices are various batteries, supercapacitors, and flywheels.

For example, the final electrical load used is a resistive load, an inductive load, or a capacitive load, or a combination thereof.

It should be noted that the present invention has been described above by way of example only with reference to the specific embodiments thereof, but they are merely illustrative, and the invention is not limited to the form of the above embodiments. According to the principles of the present invention, various changes and modifications of the above-described embodiments in accordance with the above-described technical concept are all within the scope of the present invention.

Claims

Rights request

A method of piezoelectric power generation using automobile vibration energy, comprising the steps of: placing a piezoelectric device in a vehicle suspension system, generating energy using vibration energy, and storing and utilizing it as a power supply.

2. The method of piezoelectric energy generation using automotive vibration energy according to claim 1, further comprising the steps of:

1) adding at least one piezoelectric device to the suspension system of the vehicle for absorbing vibration energy in the suspension of the vehicle, the piezoelectric material in the piezoelectric device as a working medium, converting the vibration energy into electrical energy under the action of the piezoelectric effect ;

2) sending the electrical energy generated by the piezoelectric device to the power conversion device to adjust and transform the electrical energy;

3) The power conversion device adjusts and transforms the power to the energy storage device or the final electrical load to store or utilize the electrical energy.

The method of claim 2, wherein the power conversion device controls the charging voltage of the energy storage device when the power converted by the power conversion device is received by the energy storage device. And current; when the power converted and converted by the power conversion device is received by the final electrical load, the power conversion device controls the supply voltage and current of the final electrical load.

4. The method of piezoelectric vibration generation using automobile vibration energy according to claim 2, wherein

The adjustment and transformation of the electrical energy by the power conversion device includes the following steps:

The method according to claim 2, wherein the power conversion device includes a control module having a controller as a core, and a sensor for detecting body motion is installed, and is executed by the controller. The control strategy is to semi-actively control the vibration of the vehicle while using the vibration energy of the vehicle to generate electricity.

6. A vibration energy piezoelectric power generation system for a vehicle, characterized in that the system comprises:

At least one piezoelectric device disposed in the suspension system of the vehicle, the piezoelectric device being coupled in series with a spring of the suspension system of the vehicle for converting vibrational energy into electrical energy;

At least one energy storage device or the final electrical load used for storage and adjustment using the power conversion device Electric energy

The piezoelectric device is connected to a power conversion device that is connected to an energy storage device or an electrical load that is ultimately used.

7. The automotive vibration energy piezoelectric power generation system according to claim 6, wherein: said piezoelectric device comprises a lower piston rod, an upper piston, a hydraulic cylinder and a piezoelectric element; and one end of the lower piston rod and the upper piston In the hydraulic cylinder, and filled with liquid in between; the lower piston rod is connected with the damping spring of the suspension system, and the damping spring transmits the force formed by the mass vibration of the vehicle bottom to the lower piston rod, and is transmitted to the upper piston through the liquid pressure, a piezoelectric element is placed between the piston and the vehicle body;

The piezoelectric element employs a piezoelectric stack in which a plurality of piezoelectric sheets are connected in parallel. ,

The automobile vibration energy piezoelectric power generation system according to claim 7, wherein: the piezoelectric element in the piezoelectric device is a piezoelectric ceramic or a ferroelectric piezoelectric material or a piezoelectric composite material;

9. The automotive vibration energy piezoelectric power generation system according to claim 6, wherein the power module of the power conversion device comprises a full bridge rectifier device and a DC/DC converter; and the full bridge rectifier device and the piezoelectric element The output terminal is connected to convert the alternating current generated by the piezoelectric element into direct current; the DC/DC converter is connected to the full bridge rectifier device for adjusting the voltage and current outputted by the pulse full bridge rectifier; in the DC/DC converter The power switching device performs an instruction communicated by the control signal.

10. The automotive vibration energy piezoelectric power generation system according to claim 6, wherein the control module of the power conversion device comprises: a sensor, a filter circuit, a controller, and an opto-isolation circuit; the sensor is placed in the piezoelectric device and the electric power The power module of the transforming device is used to obtain a signal required by the controller; the controller is connected to the sensor through the filter circuit to obtain a signal obtained by the sensor, and output a control signal; the power of the control signal sent to the power module through the photoelectric isolation circuit The control terminal of the switching device.