Lead screw mechanism damping pressure power generation and electric energy conversion device for electric vehicle

Abstract

The lead screw mechanism damping pressure power generation and electric energy conversion device comprises a pressure plate, a screw rod, a spring, a rotating structure, a piezoelectric power generation structure, an electric energy collection structure and a piezoelectric energy acquisition structure, the pressure plate is arranged in a damping plate of damping equipment, one end of the screw rod is connected with the pressure plate and penetrates through the pressure plate, and the other end of the screw rod is connected with the spring. The other end of the spiral rod penetrates through the rotating structure, the spring is wound outside the spiral rod and used for conducting downward compression along with the spiral rod to generate elastic potential energy, the piezoelectric power generation structure is arranged outside the rotating structure and used for generating electric energy under the rotating effect of the rotating structure, and the electric energy collecting structure is connected with the piezoelectric power generation structure and the piezoelectric energy obtaining structure. And the piezoelectric energy acquisition structure is used for processing the electric energy and supplying power to a battery of the electric vehicle. Compared with the prior art, the method has the advantages of increasing the endurance mileage of the electric vehicle and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of pressure power generation, in particular to a screw rod mechanism shock absorption pressure power generation and electric energy conversion device for electric vehicles. BACKGROUND

[0002] In today's global context, with the increasing awareness of environmental protection and the continuous optimization of energy structure, electric vehicles, as representatives of clean energy transportation tools, are gradually receiving widespread attention and promotion. Electric vehicles, with their zero emissions, low noise, high energy efficiency and other significant advantages, have shown broad application prospects in urban transportation, logistics distribution, personal travel and other fields. However, despite the significant progress made in electric vehicle technology in recent years, its development still faces many challenges. Among them, the energy supply problem is particularly prominent, becoming a key factor restricting the widespread application of electric vehicles. The range of electric vehicles and the convenience of charging facilities have always been the focus of users and an important bottleneck that needs to be broken through in electric vehicle technology. Although the traditional battery energy storage method has solved the energy problem of electric vehicles to some extent, its shortcomings such as heavy weight, high cost, long charging time cannot be ignored. Therefore, how to improve the energy utilization efficiency of electric vehicles and reduce dependence on traditional power grids has become an important direction of electric vehicle technology research.

[0003] In this context, self-power generation technology has gradually become a research hotspot in the field of electric vehicles. Self-power generation technology aims to collect various forms of energy generated during the driving process of electric vehicles, such as vibration energy, wind energy, solar energy, etc., and convert them into electrical energy to provide additional power support for the vehicle. This technology not only extends the range of electric vehicles, but also reduces the frequency of charging and improves the energy self-sufficiency of the vehicle. Among them, the self-power generation technology that utilizes the vibration and mechanical energy generated during the driving process of electric vehicles is particularly eye-catching. This is because the transmission system, suspension system, tires and other components of electric vehicles will generate a large amount of vibration and mechanical energy during driving, and if these energies can be effectively collected and converted into electrical energy, it will provide a new solution for the energy management of electric vehicles, further promoting the development and application of electric vehicle technology.

[0004] As an important component of electric vehicle transmission system, screw mechanism plays a crucial role in the operation of electric vehicles. Its main function is to convert the rotary motion of the motor into the linear motion of the vehicle, thereby realizing the driving of electric vehicles. However, the design of traditional screw mechanism often only focuses on its transmission efficiency and stability, while ignoring its potential energy recovery value. In fact, screw mechanism will generate a large amount of mechanical energy and vibration energy during operation, and if these energies can be effectively collected and converted into electrical energy, it will provide a new idea for the self-power supply technology of electric vehicles and further improve the energy utilization efficiency of electric vehicles. Piezoelectric power generation technology, as a new type of energy conversion technology, has the advantages of simple structure, high conversion efficiency and easy integration. This technology uses the piezoelectric effect of piezoelectric materials to convert mechanical energy into electrical energy under external force. In recent years, with the continuous development of piezoelectric materials and their conversion technology, piezoelectric power generation devices have shown broad application prospects in aerospace, military, civilian communication and other fields. Especially in the power supply of micro-electronic devices and micro-electromechanical systems, piezoelectric power generation devices have become an important self-power supply solution. The continuous maturity and wide application of piezoelectric power generation technology provide strong technical support for the research and development of electric vehicle screw mechanism pressure power generation device. Therefore, it is of great research significance and application value to combine piezoelectric power generation technology with electric vehicle screw mechanism and develop a new type of electric vehicle screw mechanism pressure power generation device.

[0005] In foreign countries, especially in developed countries such as Europe, the United States, and Japan, the research on new screw mechanism pressure power generation is relatively early and in-depth. Research institutions and enterprises in these countries have made some important technical breakthroughs and application results in this field. Some foreign research teams have successfully developed high-performance screw mechanisms and achieved high conversion efficiency. They have optimized the screw material, structure, and process, and improved the working principle and control strategy of the generator, improving the overall performance of the power generation system. In addition, these research teams have explored the application of screw mechanism pressure power generation in different fields, such as automobiles, buildings, and aerospace. In the early 19th century, scientists began to explore the possibility of converting mechanical energy into electrical energy. In this period, traditional power generation technologies such as water turbines and steam engines had been widely used, while pressure power generation technology was still in its infancy. Early research on pressure power generation focused on the use of gas pressure and liquid pressure. Scientists generated energy by compressing and expanding gases, and used this energy to drive generators. However, due to technical and theoretical limitations, these early studies did not achieve significant results. In 1880, the Curies discovered that applying pressure or tension to a quartz crystal in a specific direction would cause an electric charge to appear on the surface of the quartz crystal, and the density of the electric charge was proportional to the size of the external force applied, which was the positive piezoelectric effect of piezoelectric materials. Subsequently, in 1881, the Curies verified the inverse piezoelectric effect through experiments and obtained the positive and inverse piezoelectric coefficients of quartz crystals. In 1894, Voigt pointed out that the condition for a medium to have piezoelectricity is that its structure does not have a center of symmetry. Among the 32 point groups, only 20 point groups do not have a center of symmetry, and only the dielectric medium belonging to these 20 point groups can be piezoelectric. Quartz is a representative of piezoelectric crystals, and frequency control components such as oscillators and filters can be made using the piezoelectric effect of quartz. During World War II, Langmuir, the successor of the Curies, used quartz to make underwater ultrasonic detectors to detect German submarines, thus opening a glorious chapter in the history of piezoelectric applications. In addition to quartz crystals, roxyl salt and BaTiO ceramic were also applied. In 1947, Robert in the United States polarized BaTiO ceramic under high pressure and obtained piezoelectricity of piezoelectric ceramic. Subsequently, the United States and Japan actively carried out research on the application of BaTiO piezoelectric ceramic to make ultrasonic transducers, audio transducers, pressure sensors, and other measuring devices, as well as piezoelectric devices such as filters and resonators. This extensive application research continued until the mid-1950s. In the early 20th century, with the development of the industrial revolution and the progress of science and technology, pressure power generation technology made a breakthrough. In this period, people began to research the use of hydraulic transmission principles for power generation. Hydraulic transmission is a way to convert fluid pressure into mechanical energy, and through this way, the pressure of water or other liquids can be converted into the mechanical energy required by the generator.In the 1920s, American scientist Gordon Peebles successfully developed the first practical hydraulic drive generator. This invention laid the foundation for the development of later pressure power generation technology. In 1955, B. Jaffe et al. discovered lead zirconate titanate, i.e. PZT piezoelectric ceramic, which is superior to BaTiO3 in piezoelectricity, greatly accelerating the application of piezoelectric ceramic and bringing about a new situation in the application of piezoelectricity. Some applications that were difficult to realize in the BaTiO era, especially piezoelectric ceramic filters and resonators, and mechanical filters, etc., have been rapidly realized with the emergence of PZT piezoelectric ceramic. SAW devices such as SAW filters, delay lines and oscillators using piezoelectric materials have also been realized since the late 1970s. Organic polymer piezoelectric materials (PVDF), which attracted people's attention in the early 1970s, have now basically matured and have reached a production scale. Today, with the need for environmental protection, in order to benefit future generations and achieve sustainable development, lead-free piezoelectric materials are also being researched.

[0006] In China, the research on new screw mechanism pressure power generation is gradually rising. Some universities and research institutions have begun to focus on this field and try to explore its power generation performance and optimization methods through theoretical modeling, simulation analysis and experimental research. These studies not only focus on the design and optimization of the screw mechanism, but also involve the improvement of the working principle of the generator and the integration and testing of the overall system. Although China's research started late, in recent years, some important progress has been made. Some research teams have successfully designed and manufactured new screw mechanisms and verified their power generation performance through experiments. At the same time, some research teams are committed to improving the conversion efficiency of the screw mechanism and exploring its application potential in different application scenarios. Miao Hui of Huazhong University of Science and Technology designed a new type of pressure power generation device, which combines piezoelectric material power generation and hydraulic system power generation into a whole device. The piezoelectric material power generation mainly provides a continuous low voltage power supply for the control system of the hydraulic power generation, and the hydraulic system power generation is the main part of the whole device. The piezoelectric ceramic is used as the piezoelectric material. The electric energy generated by the piezoelectric ceramic is transmitted through the pressure sensor to the analog electric signal, and the A / D converter converts the analog electric signal into digital signal that can be accepted by the single-chip microcomputer. Through the comparison of these digital signals, the single-chip microcomputer makes corresponding control actions. At this stage, the research on piezoelectric material power generation in China has gradually deepened. Su Jiake of the Forestry College of Northeast Forestry University and Zhu Zimin of the College of Mechanical and Electrical Engineering designed a pressure power generation system based on walking. The piezoelectric material PVDF floor is used, which has the characteristics of light weight, high voltage output, wide frequency influence range, good chemical stability, large dielectric constant, and soft texture compared with piezoelectric ceramic. The device not only generates electricity by pressing the piezoelectric material PVDF through movement pressure, but also compresses air through the piston connecting rod device, which acts on the PVDF to generate secondary power, greatly improving the power generation efficiency of the piezoelectric material. The system uses S-882Z series charging pump to design a boost circuit without starting circuit, which increases the stability of the circuit. In 2018, Guangdong Electric Power Industry Vocational and Technical School designed a pressure power generation-based power system. The system uses Cymbal piezoelectric vibrator and uses PMUADP5091 based on ADI company as the core chip of the energy harvesting circuit, and uses super capacitor as energy storage. The design embeds multiple Cymbal piezoelectric vibrators in a thin cylindrical box, short-circuits the metal end caps of adjacent Cymbal piezoelectric vibrators, and places them in a way that the polarization directions are opposite. By connecting the wires, multiple piezoelectric vibrators can be connected in parallel. In the case of consistent output power, multiple Cymbal piezoelectric vibrators connected in parallel can increase the output current of the transducer system, reduce the output impedance of the transducer system, and reduce the matching difficulty of the subsequent energy storage circuit.

[0007] From the current research status at home and abroad, although developed countries have conducted a large number of researches on piezoelectric power generation technology and have achieved certain experimental results, these researches mainly focus on improving energy conversion efficiency, optimizing device structure, etc., and the research on piezoelectric power generation technology in the field of electric vehicles is relatively less. At present, the research on piezoelectric power generation technology in the field of electric vehicles also needs to be further explored. With the continuous expansion of the electric vehicle market and the increasing demand of consumers for range, charging convenience and other needs, the market demand for "electric vehicle screw mechanism pressure power generation device" will continue to grow. The specific performance is as follows:

[0008] (1) The popularity of electric vehicles is increasing: With the enhancement of global environmental awareness and the transformation of energy structure, electric vehicles, as representatives of clean energy transportation tools, will continue to increase their popularity. This will directly drive the market demand for related parts and technologies.

[0009] (2) Range anxiety is alleviated: The device can effectively collect and utilize the vibrations and mechanical energy generated during the driving of electric vehicles, providing additional power support for the vehicle, thereby extending the range. This will greatly alleviate the range anxiety of consumers and improve the market competitiveness of electric vehicles.

[0010] (3) Charging facilities construction lags behind: The current charging facility construction lags behind the development speed of the electric vehicle market. The application of the device can to some extent make up for this deficiency, reduce the dependence on charging facilities, and improve the convenience of electric vehicles.

[0011] As an innovative energy conversion technology, although the screw mechanism pressure power generation has potential application prospects, there are still some defects and challenges. The following are some main defects of the current new screw mechanism pressure power generation:

[0012] (1) Conversion efficiency problem

[0013] The conversion efficiency of the screw mechanism in converting pressure energy into electrical energy still needs to be improved. This is mainly limited by material performance, mechanism design and power generation mechanism. At present, the deformation or displacement generated by the screw mechanism when subjected to pressure may not be completely and efficiently converted into electrical energy, resulting in a large energy loss.

[0014] (2) Material selection and durability

[0015] The material selection of the screw mechanism has an important influence on its performance and service life. At present, some materials may not meet the requirements under high pressure and high frequency working conditions, resulting in unstable performance and easy damage of the mechanism. Therefore, finding materials with excellent mechanical properties, wear resistance and corrosion resistance has become an important direction of current research.

[0016] (3) Complexity of structure design

[0017] To achieve high-efficiency pressure generation, the structural design of the screw mechanism may be relatively complex. This increases the manufacturing cost and difficulty, and may also affect the stability and reliability of the mechanism. Simplifying the structure and improving manufacturing efficiency are one of the problems that need to be solved in current research.

[0018] (4) System integration and optimization

[0019] Integrating the screw mechanism with the generator, control system, and other components to form a complete power generation system requires solving a series of technical problems. Currently, the integration and optimization of the system still face challenges, such as how to achieve coordinated work between components and improve overall performance.

[0020] (5) Application scenario limitations

[0021] Although the screw mechanism pressure generation has potential application value, its application scenarios are still limited at present. This is mainly due to factors such as technical maturity, cost, and market demand. In order to expand its application range, it is necessary to further reduce costs, improve performance, and explore more application scenarios and market potential.

[0022] Therefore, the screw mechanism pressure generation still has some defects and challenges in terms of conversion efficiency, material durability, structural design, system integration, and application scenarios. In order to promote the development and application of this technology, it is necessary to continue in-depth research and technological innovation to solve these key problems. SUMMARY

[0023] The purpose of the present application is to provide a screw mechanism shock absorption pressure generation and electric energy conversion device for electric vehicles, which provides additional power support for electric vehicles.

[0024] The purpose of the present application can be achieved by the following technical solutions:

[0025] A screw mechanism shock-absorbing pressure power generation and electric energy conversion device for an electric vehicle, the shock-absorbing pressure power generation device being connected to a shock-absorbing device in the electric vehicle and comprising a pressure plate, a spiral rod, a spring, a rotating structure, a piezoelectric power generation structure, an electric energy collection structure, and a piezoelectric energy acquisition structure. The pressure plate is disposed in the shock-absorbing plate of the shock-absorbing device. During shock absorption, the pressure plate is compressed to drive the pressure plate downward. One end of the spiral rod is connected to the pressure plate and passes through the pressure plate, and the other end passes through the rotating structure. The spiral rod is configured to be compressed downward under the drive of the pressure plate to drive the rotating structure to rotate. The spring is wound around the outside of the spiral rod and is configured to be compressed downward with the spiral rod to generate elastic potential energy. The piezoelectric power generation structure is disposed outside the rotating structure and is configured to generate electric energy under the action of the rotation of the rotating structure. The electric energy collection structure is respectively connected to the piezoelectric power generation structure and the piezoelectric energy acquisition structure and is configured to transmit the generated electric energy to the piezoelectric energy acquisition structure via an electric signal. The piezoelectric energy acquisition structure is configured to process the electric energy and power the electric vehicle battery.

[0026] Furthermore, the rotating structure includes a ratchet and an internal gear, the other end of the spiral rod passes through the ratchet, the ratchet is connected to the internal gear and is arranged outside the internal gear, and when the ratchet rotates forward, the ratchet gear drives the internal gear to rotate, and when the ratchet rotates reversely, the ratchet gear is separated from the gear of the internal gear, and the internal gear does not rotate.

[0027] Furthermore, it also includes an upper cover, which is arranged on the upper part of the ratchet, and the upper part of the internal gear is connected to the upper cover through a slot.

[0028] Furthermore, the upper cover has a built-in bearing.

[0029] Furthermore, the piezoelectric power generation structure includes a metal pick and a piezoelectric sheet. The metal pick is installed on the outer periphery of the rotating structure and rotates with the rotating structure. The piezoelectric sheet is installed on the power collection structure through a slot. The metal pick is used to vibrate the piezoelectric sheet to generate electrical energy.

[0030] Furthermore, the piezoelectric energy acquisition module includes a piezoelectric transducer, a rectifier interface circuit and a power management circuit connected in sequence, the piezoelectric transducer is used to output an AC voltage based on the received electrical signal, the rectifier interface circuit is used to convert the AC voltage into a DC voltage, and the power management circuit is used to adjust the DC voltage.

[0031] Furthermore, the electrical model of the piezoelectric transducer is equivalent to an AC current source i P In parallel with its parasitic capacitance C P .

[0032] Furthermore, the rectifier interface circuit includes a full-bridge rectifier circuit, a synchronous charge extraction circuit and a P-SSHI circuit. The full-bridge rectifier circuit includes bridge-connected diodes D1, D2, D3 and D4. The positive electrodes of D1 and D3 are connected to form a positive input terminal of the full-bridge rectifier circuit. The negative electrodes of D2 and D4 are connected to form a negative input terminal of the full-bridge rectifier. The negative electrodes of D1 and D2 are connected to each other, and the positive electrodes of D3 and D4 are connected to each other. The connection points at the two locations respectively form the positive output terminal and negative output terminal of the full-bridge rectifier.

[0033] The working process of the full-bridge rectifier circuit includes:

[0034] When the AC current source i P In the positive half cycle, the voltage at point P is V P Greater than the voltage V at point N N , D1 and D4 are turned on, D2 and D3 are turned off, and the AC current source i of the piezoelectric transducer P It is transmitted to D1, passes through the load RL, and then transmitted back to the piezoelectric transducer from D4. Points P and N are the two connection terminals that are drawn from the piezoelectric transducer and connected to the full-bridge rectifier circuit.

[0035] When the AC current source i P In the negative half cycle, the voltage at point P is V P Less than the voltage V at point N N , D2 and D3 are turned on, D1 and D4 are turned off, and the AC current source i of the piezoelectric transducer P Transmitted to D2, through the load RL, and then transmitted back to the piezoelectric transducer from D3;

[0036] The minimum threshold voltage of the bridge rectifier circuit is V REC +2V D , the energy Q consumed by the bridge rectifier circuit during half a cycle due to charging and discharging loss for:

[0037] Q loss =C P ×2(V REC +2V D ) (1)

[0038] Where C p is the parasitic capacitance, V REC is the voltage across the load RL, V D is the forward voltage drop of the diode;

[0039] The energy Q obtained in half a cycle of the bridge rectifier circuit p for:

[0040]

[0041] Combining equations (1) and (2), we can get the average output power P of the bridge rectifier circuit as:

[0042]

[0043] Where, f EX is the charge extraction frequency of the piezoelectric transducer, V OC is the voltage across the piezoelectric transducer;

[0044] Derivative (3) and take the derivative as 0, when V REC =V OC / 2-V D When , the maximum output power of the bridge rectifier circuit is:

[0045] P FBR =C P ×f EX ×(V OC -2V D ) 2 (4)

[0046] Where, P FBR is the maximum output power.

[0047] Furthermore, the synchronous charge extraction circuit is connected between the full-bridge rectifier circuit and the load RL, and the synchronous charge extraction circuit is kept consistent with the vibration period of the piezoelectric transducer through the switch of the Buck-Boost converter.

[0048] Furthermore, the P-SSHI circuit is connected between the piezoelectric transducer and the full-bridge rectifier circuit. The P-SSHI circuit includes an inductor L and a switch S, which is used to accelerate the parasitic capacitance C of the piezoelectric transducer by using LC resonance. P The voltage V OC Flip, the working process of the P-SSHI circuit includes:

[0049] When the AC current source i P When it is 0, the switch S is closed to form a resonant LC circuit;

[0050] After 1 / 2 resonant period, the switch S is turned off;

[0051] When the parasitic capacitance C of the piezoelectric transducer P The voltage across the two terminals V OC Reach the minimum threshold voltage V of the full-bridge rectifier circuit REC +2V D After that, the P-SSHI circuit transmits the energy to the load through the full-bridge rectifier circuit and supplies power to it until the AC current source i of the piezoelectric transducer is P When it drops to 0, the switch S is closed again and the next vibration cycle begins, repeating the above voltage VOC Flip process

[0052] Wherein when the alternating current source i P When the polarity changes from positive to negative, the voltage V OC The flip ends up with the maximum voltage V max Indicated as:

[0053]

[0054] In the formula, V L The load voltage, Q1 is the quality factor related to the damping and resonance characteristics of the circuit, which is used to measure the energy loss.

[0055] Compared with the prior art, the present application has the following beneficial effects:

[0056] (1) The present application captures the braking pressure of the electric vehicle when braking, the inertial force when accelerating, or the vibration pressure generated when driving on bumpy roads, and converts the mechanical energy generated by the pressure into electrical energy through the screw rod, spring, rotating structure, and piezoelectric power generation structure. The piezoelectric energy acquisition structure processes the electrical energy and supplies power to the electric vehicle battery, providing additional power support for the electric vehicle.

[0057] (2) The battery pack of the traditional electric vehicle is one of the most expensive and limited life components in the vehicle, while the lead screw mechanism pressure power generation device of the present application is a mechanical energy recovery technology, which has higher environmental tolerance and longer service life compared to pure electronic components. It can work stably under various harsh road and weather conditions, reducing the additional cost caused by battery aging, damage or replacement.

[0058] (3) The present application also focuses on improving the environmental adaptability and sustainability of electric vehicles. By integrating the lead screw mechanism pressure power generation device, the electric vehicle can better cope with energy loss caused by poor road conditions when driving under complex and variable road conditions. At the same time, the use of this device also helps to reduce dependence on traditional fossil fuels, reduce carbon emissions and environmental pollution during the operation of electric vehicles, and promote the green transformation of the entire transportation industry.

[0059] (4) The piezoelectric energy acquisition structure of the present application optimizes the circuit design, realizes AC-DC conversion, improves energy conversion efficiency through rectifier interface circuit, and adjusts through power management circuit to be inconsistent with the load voltage, providing stable power supply for the subsequent load.

[0060] (5) The application provides an instant power supplement mechanism for the electric bicycle, is environment-friendly, can provide power for the electric bicycle in real time, does not need the user to additionally find a charging facility or wait for charging, solves the power self-provision problem of the electric bicycle during travel, and enhances the endurance, convenience and practicality of the electric bicycle.

[0061] (6) The traditional electric bicycle energy utilization mode is relatively single, mainly through battery power supply, the application introduces the screw rod mechanism pressure power generation device, improves the diversity of energy utilization, makes the mechanical energy during travel effectively utilized, is converted into electric energy to supplement the battery, and thus improves the overall energy utilization efficiency.

[0062] (7) The application captures the pressure generated during travel of the electric bicycle through the screw rod mechanism, effectively converts into electric energy, aims to realize power supplement of the electric bicycle during travel. This mode can significantly prolong the endurance of the electric bicycle, reduces the dependence on external charging facilities, and thus increases the endurance of the electric bicycle. BRIEF DESCRIPTION OF DRAWINGS

[0063] Figure 1 It is a schematic diagram of the shock-absorbing pressure power generation device of the application;

[0064] Figure 2 It is an application scene of the device on the electric vehicle;

[0065] Figure 3 It is a schematic diagram of the piezoelectric energy acquisition structure of the application;

[0066] Figure 4 It is a schematic diagram of the positive piezoelectric effect and the inverse piezoelectric effect of the application;

[0067] Figure 5 It is a mechanical model of the piezoelectric transducer of the application;

[0068] Figure 6 It is an electrical model of the piezoelectric transducer of the application;

[0069] Figure 7 It is the FBR circuit and waveform of the application, wherein, (a) is the FBR circuit, and (b) is the waveform;

[0070] Figure 8 It is the SECE circuit and waveform of the application, wherein, (a) is the SECE circuit, and (b) is the waveform;

[0071] Figure 9 It is the P-SSHI circuit and waveform of the application, wherein, (a) is the P-SSHI circuit, and (b) is the waveform,

[0072] Wherein, 1: pressure plate, 2: screw rod, 3: upper cover, 4: ratchet wheel, 5: internal gear, 6: metal tab, 7: piezoelectric sheet, 8: electric energy collection structure, 9: shock absorbing plate, 10: outer wall, 11: spring, 12: piezoelectric energy acquisition structure. DETAILED DESCRIPTION

[0073] The application will be described in detail below with reference to the drawings and specific embodiments. The embodiments are implemented on the basis of the technical solutions of the application, and detailed implementation modes and specific operation processes are given, but the protection scope of the application is not limited to the following embodiments.

[0074] The present embodiment provides a screw mechanism shock absorbing pressure power generation and electric energy conversion device for electric vehicles, as shown in Figure 2 The right side is a hydraulic shock absorbing hydraulic pipe, and the left side is a shock absorbing pressure power generation device. The hydraulic shock absorbing device is used to convert the pressure generated during the driving of the electric bicycle into mechanical energy through the screw mechanism, and further convert the mechanical energy into electric energy to supply power to the electric vehicle, as shown in Figure 2 .

[0075] Specifically, as shown in Figure 1 The shock absorbing pressure power generation device includes a pressure plate 1, a screw rod 2, a spring 11, a rotating structure, a piezoelectric power generation structure, an electric energy collection structure 8, and an upper cover 3. The rotating structure includes a ratchet wheel 4 and an internal gear 5. The piezoelectric power generation structure includes a metal tab 6 and a piezoelectric sheet 7. In addition, in order to use the electric energy generated by the shock absorbing pressure power generation device to actually supply power to the electric bicycle, the present embodiment further introduces a piezoelectric energy acquisition structure 12 connected with the electric energy collection structure 8. The piezoelectric energy acquisition structure 12 includes a piezoelectric transducer, a rectifier interface circuit, and a power management circuit connected in sequence.

[0076] The pressure plate 1 is arranged in the damping plate 9 of the damping device, and the pressure plate 1 is used to compress the damping plate 9 to drive the pressure plate 1 to move downward during damping, one end of the screw rod 2 is connected with the pressure plate 1 and passes through the pressure plate, the other end passes through the ratchet wheel 4, the screw rod 2 is used to compress downward under the driving of the pressure plate 1 to drive the ratchet wheel 4 to rotate, the spring 11 is wound outside the screw rod 2 and is compressed downward under the action of the elastic force to generate elastic potential energy, the ratchet wheel 4 is connected with the internal gear 5 and is arranged outside the internal gear 5, and when the ratchet wheel 4 rotates forward, the gear of the ratchet wheel 4 drives the internal gear 5 to rotate, when the ratchet wheel 4 rotates reversely, the gear of the ratchet wheel 4 is separated from the gear of the internal gear 5, and the internal gear 5 does not rotate, the piezoelectric power generation structure is arranged outside the internal gear 5 and is used to generate electric energy under the rotation of the rotation structure, the electric energy collection structure 8 is connected with the piezoelectric power generation structure and is used to collect the generated electric energy, the upper cover 3 is arranged on the upper portion of the ratchet wheel 4, the upper portion of the internal gear 5 is connected with the upper cover 3 through a clamping groove, the upper cover 3 is internally provided with a bearing to stabilize the structure of the device, the metal tab 6 is inserted around the internal gear 5, and the piezoelectric sheet 7 is arranged on the electric energy collection structure 8 through a clamping groove.

[0077] The piezoelectric energy acquisition structure 12 is connected with the electric energy collection structure 8, the piezoelectric transducer is used to output alternating voltage based on the received electric signal, the rectifier interface circuit is used to convert the alternating voltage into direct current voltage, and the power management circuit is used to adjust the direct current voltage.

[0078] The working principle of the device is as follows:

[0079] When the electric vehicle encounters a deceleration strip, the damping device works, and the damping plate 9 is compressed. The pressure plate 1 is connected with the screw rod 2, and the pressure plate 1 is arranged in the damping plate 9, the pressure plate 1 drives the screw rod 2 to compress downward. At this time, the ratchet wheel 4 attached to the screw rod 2 is driven to rotate by the downward displacement of the screw rod 2, and the internal gear 5 attached to the ratchet wheel 4 is also driven to rotate. The metal tab 6 is inserted around the internal gear 5, and the metal tab 6 drives the piezoelectric sheet 7 around to vibrate. The vibrating piezoelectric sheet 7 generates electric energy, the electric energy collection structure 8 for fixing the piezoelectric sheet 7 collects the electric energy generated by the piezoelectric sheet 7, and transmits the electric energy to the piezoelectric energy acquisition structure to convert the electric energy into alternating current and direct current and adjust the electric energy to supply power to the battery of the electric vehicle.

[0080] When the pressure disappears, the elastic potential energy of the spring 11 is released, and the pressure plate 1 rebounds. In this process, the internal gear 5 does not rotate: the spring 11 rebounds, the pressure plate 1 drives the screw rod 2 to produce upward displacement, the screw rod 2 rotates while driving the ratchet wheel 4 to rotate in the opposite direction, and the design of the connection between the ratchet wheel 4 and the internal gear 5 prevents the ratchet wheel 4 from driving the internal gear 5 to rotate, which can effectively prevent the metal tab 6 from reversing the piezoelectric sheet 7 to cause vibration cancellation and reduce power generation. Even if the device is used for a long time, the friction between the screw rod 2 and the ratchet wheel 4 increases, the screw rod 2 drives the ratchet wheel 4 to move upward, the gear of the ratchet wheel 4 is separated from the gear of the internal gear 5, so the internal gear 5 still does not rotate.

[0081] In the device, the piezoelectric sheet 7 is fixed on the electric energy collection structure 8 through a clamping groove design. The internal gear 5 receives a downward force from the ratchet wheel 4 during rotation, and the connection between the internal gear 5 and the electric energy collection structure 8 adopts a clamping groove design, so the electric energy collection structure 8 can limit the downward displacement of the internal gear 5. The clamping groove part is made of a material with a very small dynamic friction coefficient, which can reduce the friction loss between the internal gear 5 and the electric energy collection structure 8 at the clamping groove connection during rotation.

[0082] The embodiment also optimizes the circuit design for the piezoelectric energy acquisition structure 12, as shown in Figure 3 The structure is composed of a piezoelectric transducer (PZT), a rectifier interface circuit, and a power management circuit, which can effectively detect vibration energy and transmit piezoelectric energy to a miniature electronic device to provide power. PZT can convert external piezoelectric vibration energy into electrical energy to power the load. The output of PZT is an alternating voltage, while most electronic load circuits and devices are powered by direct current. Therefore, between PZT and the load circuit, a rectifier interface circuit is needed to convert AC to DC, which can also improve energy conversion efficiency. After AC-DC conversion, the voltage is usually inconsistent with the load voltage, and a power management circuit is needed to adjust it to provide a stable power supply for the load.

[0083] (1) Piezoelectric transducer

[0084] Piezoelectric transducers can convert vibration energy into electrical energy because they use the piezoelectric effect of piezoelectric materials to achieve this purpose. The schematic diagram of the positive piezoelectric effect and the inverse piezoelectric effect is shown in the attached Figure 4 The mechanical model of the piezoelectric transducer is shown in the attached Figure 5

[0085] When the vibration frequency in the environment is close to the working frequency of the piezoelectric transducer, the piezoelectric transducer can be considered as an equivalent model in electrical terms as shown in the attached Figure 6 P ​​Parallel on its parasitic capacitance C P . Wherein, the sigma M in the figure represents the vibration energy of the piezoelectric transducer, L M represents the effective mass of the piezoelectric transducer, R M represents the mechanical damping of the piezoelectric transducer, C M refers to the material stiffness of the piezoelectric transducer, and n is the coupling coefficient of the transformer. The electrical model of the piezoelectric transducer is shown in the attached Figure 6 .

[0086] The rectifier interface circuit in this embodiment includes a full-bridge rectifier circuit, a synchronous charge extraction circuit and a P-SSHI circuit, which undertake the function of converting the alternating voltage output by the piezoelectric transducer into direct current voltage, and are the core link of the rectification process. The power management circuit is an independent later-stage module, which, on the basis of the direct current voltage output by the rectifier interface circuit, adjusts the voltage to the range suitable for the battery of the electric vehicle (such as 48V, 60V, etc.) by means of Buck, Boost converter, etc., and can also cooperate with the battery management system (BMS) to optimize energy storage, prevent overcharging and overdischarging, and together with the rectifier interface circuit, guarantee the effective conversion and utilization of electric energy.

[0087] (2) Full-bridge rectifier circuit

[0088] The FBR (Full-Bridge Rectifier) circuit ((a) figure) and the waveform ((b figure)) are shown in the attached Figure 7 . In the early standard energy acquisition circuit interface circuit, the full-bridge rectifier circuit is the most commonly used structure, and the FBR is composed of four diodes D1, D2, D3 and D4, as shown in (a) of the attached Figure 7 , which can effectively provide stable current to achieve high-efficiency signal transmission. The voltage across the PZT is V OC , the voltage across the load is V REC , and the forward voltage drop of the diode is V D . The working principle is: when the current i P of the piezoelectric transducer is in the positive half cycle, at this time the voltage V P at point P is greater than the voltage V N at point N (P and N points are key nodes in the full-bridge rectifier circuit connected to the output end of the piezoelectric transducer (PZT). P and N points can be regarded as two terminal points leading out from the piezoelectric transducer and connected to the full-bridge rectifier circuit, which are used to transmit the alternating voltage signal generated by the PZT, and are the electrical connection points between the piezoelectric transducer and the rectifier circuit), diodes D1 and D4 are turned on, D2 and D3 are turned off, and the output current i L of the piezoelectric transducer is transmitted to diode D1, then through the load R L , and finally transmitted back to the PZT from diode D4; when the current i PIn the negative half cycle, the voltage V at point P is P Less than the voltage V at point N N , diodes D2 and D3 are turned on, D1 and D4 are turned off, and the output current i of the electrical sensor P Flows into diode D2 and then passes through load R L , and then flows back to the piezoelectric transducer from diode D3. Figure 7 (b), we can observe that when V OC Lower than V REC +2V D When V REC +2V D is considered to be the lowest threshold voltage of the full-bridge rectifier circuit, that is, when V OC When the voltage is lower than the threshold, the full-bridge rectifier circuit will not work properly. OC The size exceeds V REC +2V D The energy lost due to charging and discharging in the FBR circuit during half a cycle is Q loss for:

[0089] Q loss =C P ×2(V REC +2V D )

[0090] Although the full-bridge rectifier circuit has a simple structure and is relatively easy to implement, if the voltage generated by the piezoelectric transducer is low, it cannot exceed the threshold voltage V REC +2V D When the threshold voltage is , PZT cannot work properly, and a large amount of energy will be lost, as shown in the following formula, which seriously affects the efficiency of piezoelectric energy acquisition. The energy Q obtained in half a cycle of the FBR circuit is p :

[0091]

[0092] Combining the above two equations, the average output power of FBR is:

[0093] P=2×(Q P -Q loss )×V REC ×f EX

[0094] =4C P ×V REC ×f EX ×(V OC -V REC-2V D )

[0095] Take the derivative of the above formula and take it as 0. When V REC =V OC / 2-V D When , the maximum output power of FBR is:

[0096] P FBR =C P ×f EX ×(V OC -2V D ) 2

[0097] (3) Synchronous charge extraction circuit

[0098] Based on the FBR structure, the synchronous charge extraction circuit (SECE circuit) optimizes the circuit structure by inserting a Buck-Boost converter between the load and the full-bridge rectifier circuit. Figure 8 The characteristic of SECE is that the switching of the Buck-Boost converter is aligned with the vibration period of the piezoelectric transducer, thus achieving more efficient charge extraction capability. The SECE circuit (Figure (a)) and waveform (Figure (b)) are shown in the attached Figure 8 shown.

[0099] (4) P-SSHI circuit

[0100] The P-SSHI (parallel synchronous switching inductor) circuit (Figure (a)) and waveform (Figure (b)) are shown in the attached Figure 9 The parallel synchronous switching inductor technology is a technology that connects the inductor L and the switch S in parallel between the PZT and the FBR. It can effectively control the circuit and thus improve the energy conversion efficiency of the system. The circuit diagram is shown in the attached figure. Figure 9 As shown in Figure (a).

[0101] The relevant signal waveforms of the P-SSHI circuit are shown in the attached figure. Figure 9 As shown in Figure (b), when the current i P When the value is 0, the switch S is closed to form a resonant LC circuit, thereby accelerating the parasitic capacitance C of the piezoelectric transducer. P The voltage reversal speed between the inductor L and the P-SSHI circuit. After 1 / 2 resonant cycle, the switch S is turned off. Due to the energy loss in the resonance process, the parasitic capacitance C of the piezoelectric transducer P The voltage across the two terminals V OC Cannot fully reach the threshold voltage V REC +2V D When the parasitic capacitance C of the piezoelectric transducer P The voltage across the two ends VOC Slowly rises until the threshold voltage size V REC +2V D After that, the P-SSHI circuit will transmit energy to the load R through the full-bridge rectifier circuit L And power supply. Until i P Drop to zero, the switch S will be re-closed, into the next same vibration cycle, repeat the above voltage flip process. For example, when the piezoelectric transducer current i P The polarity is changed from positive to negative, the voltage V OC At the end of the voltage flip, its maximum value V max Can be expressed as:

[0102]

[0103] The piezoelectric energy source generates an alternating voltage, and the electronic load circuit and the device of the embodiment need direct current voltage for power supply and charging, so a rectifier interface circuit needs to be connected between the piezoelectric source and the load circuit to realize AC-DC conversion. By combining the existing synchronized switch inductor harvesting technology (Synchronized Switch Harvesting on Inductor, SSHI) and the synchronized switch capacitor harvesting technology (Synchronized Switch Harvesting on Capacitor, SSHC), this paper realizes a piezoelectric energy harvesting circuit based on the synchronized switch inductor and capacitor harvesting technology (Synchronized Switch Harvesting on Inductor and Capacitor, SSHIC), which obtains higher conversion efficiency in a smaller volume. The piezoelectric energy harvesting circuit based on the SSHIC technology adopts 0.18 μm standard CMOS process for layout design, and the core area is 949 × 644 μm 2 . The simulation results of the circuit show that the flip efficiency of the designed SSHIC circuit can reach 83%; in the case of open circuit voltage range of 1-2V, the MPPT circuit with coarse-fine double-loop modulation realizes peak voltage tracking efficiency up to 92.51%, peak conversion efficiency of 81.2%, and FOM of 4.02.

[0104] In summary, the screw mechanism pressure power generation device of the electric vehicle of the embodiment solves the following technical problems:

[0105] Firstly, the embodiment of the present application aims to improve the energy utilization efficiency of electric vehicles. Through innovative design of the lead screw mechanism, various mechanical pressures generated during vehicle driving can be effectively converted into electrical energy. Whether it is the braking pressure during braking, the inertial force during acceleration, or the vibration pressure generated when driving on bumpy roads, all of these can be captured and converted into useful electrical energy by the device, thereby providing additional power support for electric vehicles. This technological breakthrough is expected to significantly improve the range of electric vehicles, reduce users' dependence on charging facilities, and improve the user experience.

[0106] Secondly, the embodiment of the present application aims to extend the service life of electric vehicles and reduce their maintenance costs. The battery pack of a traditional electric vehicle is one of the most expensive and limited-life components in the vehicle. However, the lead screw mechanism pressure power generation device of the present embodiment, as a mechanical energy recovery technology, has higher environmental tolerance and longer service life compared to pure electronic components. It can work stably under various harsh road and weather conditions, reducing additional costs caused by battery aging, damage or replacement.

[0107] Furthermore, the embodiment of the present application also aims to improve the environmental adaptability and sustainability of electric vehicles. By integrating the lead screw mechanism pressure power generation device, electric vehicles can better cope with energy loss caused by poor road conditions when driving under complex and variable road conditions. At the same time, the use of this device helps to reduce dependence on traditional fossil fuels, reduce carbon emissions and environmental pollution during electric vehicle operation, and promote the green transformation of the entire transportation industry.

[0108] Finally, the embodiment of the present application also aims to solve the problem of uneven distribution of electric vehicle charging facilities. By improving the vehicle's own energy generation capacity, the present application enables electric vehicles to be "self-sufficient" to some extent, reducing dependence on external charging facilities. This not only alleviates the pressure of charging facility construction, but also provides electric vehicle users with a more convenient and free travel experience.

[0109] In summary, the main technical problems to be solved by the invention of the lead screw mechanism pressure power generation device for electric vehicles include improving the energy utilization efficiency of electric vehicles, extending the service life and reducing the maintenance cost, improving the environmental adaptability and sustainability, and solving the problem of uneven distribution of charging facilities. Through the introduction and application of this innovative technology, we hope to break through the technical bottlenecks of traditional electric vehicles and promote the green, healthy and sustainable development of the electric vehicle industry. This is not only a major contribution to the field of electric vehicle technology, but also an active exploration and practice of future green travel methods. With the continuous maturation and perfection of this technology, we have reason to believe that electric vehicles will become an important part of future urban transportation and make greater contributions to human energy saving and environmental protection.

[0110] While the preferred embodiments of the application have been described, additional variations and modifications can be made to these embodiments by those skilled in the art once they have the benefit of the present disclosure without departing from the spirit and scope of the application. Accordingly, it is intended that the appended claims include all such modifications and variations as fall within the scope of the present application.

[0111] It is apparent that those skilled in the art can make various changes and modifications to the application without departing from the spirit and scope of the application. It is therefore intended that the present application cover all such changes and modifications that are within its scope.

Claims

1. A screw mechanism shock-absorbing pressure power generation and electric energy conversion device for electric vehicles, characterized in that: The shock-absorbing pressure power generation device is connected to the shock-absorbing equipment in the electric vehicle. The shock-absorbing pressure power generation device comprises a pressure plate (1), a spiral rod (2), a spring (11), a rotating structure, a piezoelectric power generation structure, an electric energy collection structure (8) and a piezoelectric energy acquisition structure (12). The pressure plate (1) is arranged in the shock-absorbing plate (9) of the shock-absorbing equipment. The pressure plate (1) is used to compress the shock-absorbing plate (9) and drive the pressure plate (1) to move downward during shock absorption. One end of the spiral rod (2) is connected to the pressure plate (1) and passes through the pressure plate, and the other end passes through the rotating structure. The spiral rod (2) is used to press the pressure plate (9) to move the pressure plate (1) downward. 1) is driven to be compressed downward to drive the rotating structure to rotate, the spring (11) is wound around the outside of the spiral rod (2) and is used to follow the spiral rod (2) to be compressed downward to generate elastic potential energy, the piezoelectric power generation structure is arranged outside the rotating structure and is used to generate electric energy under the rotation of the rotating structure, the electric energy collection structure (8) is respectively connected to the piezoelectric power generation structure and the piezoelectric energy acquisition structure (12) and is used to transmit the generated electric energy to the piezoelectric energy acquisition structure (12) through an electric signal, and the piezoelectric energy acquisition structure (12) is used to process the electric energy and supply power to the electric vehicle battery.

2. The screw mechanism shock-absorbing pressure power generation and electric energy conversion device for electric vehicles according to claim 1, characterized in that: The rotating structure comprises a ratchet (4) and an internal gear (5), the other end of the screw rod (2) passes through the ratchet (4), the ratchet (4) is connected to the internal gear (5) and is arranged outside the internal gear (5), and when the ratchet (4) rotates in the forward direction, the gear of the ratchet (4) drives the internal gear (5) to rotate, and when the ratchet (4) rotates in the reverse direction, the gear of the ratchet (4) is separated from the gear of the internal gear (5), and the internal gear (5) does not rotate.

3. The screw mechanism shock-absorbing pressure power generation and electric energy conversion device for electric vehicles according to claim 2, characterized in that: It also includes an upper cover (3), which is arranged on the upper part of the ratchet (4), and the upper part of the internal gear (5) is connected to the upper cover (3) through a slot.

4. The screw mechanism shock-absorbing pressure power generation and electric energy conversion device for electric vehicles according to claim 3, characterized in that: The upper cover (3) is equipped with a bearing.

5. The screw mechanism shock-absorbing pressure power generation and electric energy conversion device for electric vehicles according to claim 1, characterized in that: The piezoelectric power generation structure comprises a metal pick (6) and a piezoelectric sheet (7); the metal pick (6) is mounted on the outer periphery of the rotating structure and rotates along with the rotating structure; the piezoelectric sheet (7) is mounted on the electric energy collection structure (8) through a slot; the metal pick (6) is used to generate electric energy by driving the piezoelectric sheet (7) to vibrate.

6. The screw mechanism shock-absorbing pressure power generation and electric energy conversion device for electric vehicles according to claim 1, characterized in that: The piezoelectric energy acquisition structure (12) includes a piezoelectric transducer, a rectifier interface circuit, and a power management circuit connected in sequence, wherein the piezoelectric transducer is used to output an AC voltage based on a received electrical signal, the rectifier interface circuit is used to convert the AC voltage into a DC voltage, and the power management circuit is used to adjust the DC voltage.

7. The screw mechanism shock-absorbing pressure power generation and electric energy conversion device for electric vehicles according to claim 6, characterized in that: The electrical model of the piezoelectric transducer is equivalent to an AC current source i P In parallel with its parasitic capacitance C P .

8. The screw mechanism shock-absorbing pressure power generation and electric energy conversion device for electric vehicles according to claim 7, characterized in that: The rectifier interface circuit includes a full-bridge rectifier circuit, a synchronous charge extraction circuit, and a P-SSHI circuit. The full-bridge rectifier circuit includes bridge-connected diodes D1, D2, D3, and D4. The positive electrodes of D1 and D3 are connected to form a positive input terminal of the full-bridge rectifier circuit. The negative electrodes of D2 and D4 are connected to form a negative input terminal of the full-bridge rectifier. The negative electrodes of D1 and D2 are connected to each other, and the positive electrodes of D3 and D4 are connected to each other. The connection points at the two locations respectively form a positive output terminal and a negative output terminal of the full-bridge rectifier. The working process of the full-bridge rectifier circuit includes: When the AC current source i P In the positive half cycle, the voltage V P Greater than the voltage V at point N N , D1 and D4 are turned on, D2 and D3 are turned off, and the AC current source i of the piezoelectric transducer P It is transmitted to D1, passes through the load RL, and then transmitted back to the piezoelectric transducer from D4. Points P and N are the two connection terminals that are drawn from the piezoelectric transducer and connected to the full-bridge rectifier circuit. When the AC current source i P In the negative half cycle, the voltage V P Less than the voltage V at point N N , D2 and D3 are turned on, D1 and D4 are turned off, and the AC current source i of the piezoelectric transducer P Transmitted to D2, through the load RL, and then transmitted back to the piezoelectric transducer from D3; The minimum threshold voltage of the bridge rectifier circuit is V REC +2V D , the energy Q consumed by the bridge rectifier circuit during half a cycle due to charging and discharging loss for: Q loss =C P ×2(V REC +2V D ) (1) Where C p is the parasitic capacitance, V REC is the voltage across the load RL, V D is the forward voltage drop of the diode; The energy Q obtained in half a cycle of the bridge rectifier circuit p for: Combining equations (1) and (2), we can get the average output power P of the bridge rectifier circuit as: Where, f EX is the charge extraction frequency of the piezoelectric transducer, V OC is the voltage across the piezoelectric transducer; Derivative (3) and take the derivative as 0, when V REC =V OC / 2-V D When , the maximum output power of the bridge rectifier circuit is: P FBR =C P ×f EX ×(V OC -2V D ) 2 (4) Where, P FBR is the maximum output power.

9. The screw mechanism shock-absorbing pressure power generation and electric energy conversion device for electric vehicles according to claim 8, characterized in that: The synchronous charge extraction circuit is connected between the full-bridge rectifier circuit and the load RL. The synchronous charge extraction circuit is kept consistent with the vibration period of the piezoelectric transducer through the switch of the Buck-Boost converter.

10. The screw mechanism shock-absorbing pressure power generation and electric energy conversion device for electric vehicles according to claim 8, characterized in that: The P-SSHI circuit is connected between the piezoelectric transducer and the full-bridge rectifier circuit. The P-SSHI circuit includes an inductor L and a switch S, and is used to accelerate the parasitic capacitance C of the piezoelectric transducer by using LC resonance. P The voltage V OC Flip, the working process of the P-SSHI circuit includes: When the AC current source i P When it is 0, the switch S is closed to form a resonant LC circuit; After 1 / 2 resonant period, the switch S is turned off; When the parasitic capacitance C of the piezoelectric transducer P The voltage across the two ends V OC Reach the minimum threshold voltage V of the full-bridge rectifier circuit REC +2V D After that, the P-SSHI circuit transmits the energy to the load through the full-bridge rectifier circuit and supplies power to it until the AC current source i of the piezoelectric transducer is P When it drops to 0, the switch S is closed again and the next vibration cycle begins, repeating the above voltage V OC Flipping process; When the AC current source i of the piezoelectric transducer P When the polarity changes from positive to negative, the voltage V OC The maximum voltage V max Expressed as: Where V L is the load voltage, Q1 is the quality factor related to the circuit damping and resonance characteristics, and is used to measure the energy loss.

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