Electric vehicle dynamic wireless charging self-starting method and system based on position detection

Abstract

The invention relates to the technical field of electric vehicle wireless charging, and particularly discloses an electric vehicle dynamic wireless charging self-starting method and system based on position detection. Whether the vehicle enters the charging area or leaves the charging area can be judged, and judgment can be completed only by detecting the inverter output current; and for a subsequent transmitting coil, threshold comparison is carried out by utilizing the induced voltage generated by coupling between the coils, so that starting is carried out. According to the method and the system, the electric vehicle can be accurately positioned, accurate control and switching of the transmitting coil can be realized, so that high reliability of the system is ensured, an additional detection device is not added, operation is simple and convenient, complexity and cost of the system can be remarkably reduced, and the purposes of effectively saving electric energy and realizing accurate charging are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of wireless charging of electric vehicles, and in particular to a method and system for self-starting dynamic wireless charging of electric vehicles based on position detection. Background Art

[0002] As the global energy crisis and environmental issues become increasingly prominent, electric vehicles, as a low-carbon, environmentally friendly mode of transportation, are becoming more and more popular, but problems such as long charging time, insufficient charging infrastructure, and limited range still restrict their development. Compared with traditional wired charging methods, wireless charging has significant advantages such as no electrical contact, safer charging process, more convenient use, and less space required.

[0003] Dynamic wireless charging technology can realize charging while driving, breaking through the limitations of time and space, avoiding the problem of vehicle stopping due to long-term charging, and also solving the endurance dilemma faced by electric vehicles due to battery exhaustion during long-distance driving. The primary transmitting coil of dynamic wireless charging for electric vehicles has two types: rail type and segmented type. In the segmented type, each coil controls its own switching state according to the vehicle's position information. Once the electric vehicle is detected to enter the charging area, the system needs to activate the corresponding transmitting coil through real-time position feedback.

[0004] At present, there are auxiliary detection coils, image recognition, laser radar, etc. for electric vehicle position detection. Auxiliary detection coils may be interfered by other electromagnetic wave sources, resulting in positioning errors; image processing requires strong computing power, which increases hardware requirements; laser radar is easily affected by other obstructions. These methods undoubtedly increase the cost and complexity of the system in application. Therefore, studying a simple and fast-response method for detecting the position of electric vehicle wireless charging has become an urgent technical challenge facing the current industry. Summary of the invention

[0005] The present invention provides a dynamic wireless charging self-starting method for an electric vehicle based on position detection, and solves the technical problem of how to control the switch of a transmitting coil and system status monitoring in real time to ensure the high efficiency and safety of the charging process and improve the charging efficiency.

[0006] In order to solve the above technical problems, the present invention provides a method for self-starting dynamic wireless charging of an electric vehicle based on position detection, comprising the steps of:

[0007] S1. Determine the circuit structure and parameter design of the dynamic wireless charging system for electric vehicles;

[0008] The circuit structure includes a vehicle pickup end and a plurality of identical power transmitting ends, wherein the power transmitting end includes an inverter power supply, a primary compensation network, and a transmitting coil; the vehicle pickup end includes a receiving coil, a secondary compensation network, a rectifier filter circuit, and a vehicle-end battery load; the transmitting coils of the plurality of power transmitting ends are evenly laid along the road direction;

[0009] S2, controlling the inverter power supplies of the first and last transmitting coils by phase shifting and voltage regulation to put the first and last transmitting coils in a low-power standby state, and controlling the inverter power supplies of the remaining transmitting coils to put the remaining transmitting coils in a closed state;

[0010] S3, detecting the inverter output current corresponding to the first transmitting coil and determining whether the current undergoes a first preset change, if so, turning on the first transmitting coil, if not, continuing to detect;

[0011] S4, detecting the induced voltage in the main circuit connected to the next transmitting coil and determining whether the voltage reaches the voltage threshold, if so, turning on the next transmitting coil, if not, continuing the detection;

[0012] S5, repeat step S4 until the tail section transmitting coil is turned on;

[0013] S6. Detect the inverter output current corresponding to the tail transmitting coil and determine whether the current undergoes a second preset change. If so, control the first and tail transmitting coils to resume a low-power standby state and turn off the remaining transmitting coils. Otherwise, continue detecting.

[0014] Furthermore, the inverter power supply is provided with a full-bridge inverter constructed by switch tubes Q1, Q2, Q3 and Q4, the switch tubes Q1 and Q2 are connected to form a front half arm, and Q3 and Q4 are connected to form a rear half arm;

[0015] In step S2, the inverter power supply of the first and last section transmitting coils is controlled by phase shifting and voltage regulation to put the first and last section transmitting coils in a low power consumption standby state, specifically:

[0016] The driving signals of the switch tubes Q1 and Q2 of the full-bridge inverter controlling the first and last transmitting coils are complementary, and the driving signals of Q3 and Q4 are complementary. The driving signal of Q3 lags behind Q1 by an angle θ1, so that the output voltage amplitude of the inverter is a preset value.

[0017] Further, in the step S3, the first preset change is that the inverter output current corresponding to the first section of the transmitting coil increases from the output current in the case where there is no receiving coil.

[0018] Furthermore, in step S4, the voltage threshold is determined based on the steady value and the maximum value of the voltage value sensed by the next transmitting coil when the vehicle pickup end travels from the previous transmitting coil that is turned on to the end of the next transmitting coil that is not turned on, which is calibrated in advance.

[0019] Furthermore, let U th Indicates the voltage thresholds, U0 and U m They represent the stable value and the maximum value of the voltage sensed by the next transmitting coil, respectively. The voltage threshold is set as U0+(U m -U0) / 4≤U th ≤U m -(U m -U0) / 2.

[0020] Further, in the step S6, the second preset change is when the inverter output current corresponding to the tail section transmitting coil begins to gradually decrease until it is equal to the inverter output current value when there is no receiving coil.

[0021] Furthermore, the phase shift angle θ of the full-bridge inverter of the transmitting coil is adjusted to θ2 by phase shifting to turn on the transmitting coil.

[0022] The present invention also provides an electric vehicle dynamic wireless charging self-starting system based on position detection, which applies the electric vehicle dynamic wireless charging self-starting method based on position detection, and the key lies in: the system is provided with an inverter power supply control module, an inverter output current detection module, and an induced voltage detection module;

[0023] The inverter power supply control module is used to control the inverter power supplies of the first and last transmitting coils through phase shifting and voltage regulation to put the first and last transmitting coils in a low-power standby state, and control the inverter power supplies of the remaining transmitting coils to put the remaining transmitting coils in a closed state;

[0024] The inverter output current detection module is used to detect the inverter output current corresponding to the first section transmitting coil and send it to the inverter power control module; the inverter power control module is also used to determine whether the inverter output current sent by the inverter output current detection module undergoes a first preset change, if so, the first section transmitting coil is turned on, otherwise, the detection continues; the induced voltage detection module is used to detect the induced voltage in the main circuit connected to the next section transmitting coil and send it to the inverter power control module; the inverter power control module is also used to determine whether the induced voltage sent by the induced voltage detection module reaches a voltage threshold, if so, the next section transmitting coil is turned on, otherwise, the detection continues; the inverter output current detection module, the inverter power control module, and the induced voltage detection module repeat the process until the induced voltage detection module turns on the tail section transmitting coil;

[0025] The inverter output current detection module is also used to detect the inverter output current corresponding to the tail section transmitting coil after turning on the tail section transmitting coil and send it to the inverter power supply control module; the inverter power supply control module is also used to determine whether the inverter output current corresponding to the tail section transmitting coil sent by the inverter output current detection module undergoes a second preset change. If so, the first and tail section transmitting coils are controlled to resume the low power standby state and turn off the remaining transmitting coils. Otherwise, the detection continues.

[0026] The electric vehicle dynamic wireless charging self-starting method and system based on position detection provided by the present invention can judge whether the vehicle enters and leaves the charging area by detecting the difference in the inverter output current of the first and last transmitting coils in the absence of receiving coils and in the presence of receiving coils. The judgment can be completed by only detecting the inverter output current; for the subsequent transmitting coils, the induced voltage generated by the coupling between the coils is used to compare the threshold value so as to start. The method and system can accurately locate the electric vehicle and realize the precise control and switching of the transmitting coil, thereby ensuring the high reliability of the system, and does not add additional detection devices. It is easy to operate and can significantly reduce the complexity and cost of the system, achieving the purpose of effectively saving electric energy and realizing precise charging. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a working flow chart of a method and system for dynamic wireless charging self-starting of an electric vehicle based on position detection provided by an embodiment of the present invention;

[0028] Figure 2 is a circuit structure diagram of a dynamic wireless charging system for an electric vehicle provided by an embodiment of the present invention;

[0029] Figure 3 The embodiment of the present invention provides Figure 2 Equivalent circuit diagram of

[0030] Figure 4 is a driving waveform diagram of a switch tube provided by an embodiment of the present invention;

[0031] Figure 5 It is a waveform diagram of inverter voltage and current before and after a vehicle enters the vehicle provided by an embodiment of the present invention;

[0032] Figure 6 It is a circuit topology model diagram of a single-transmitter-multiple-pickup provided by an embodiment of the present invention;

[0033] Figure 7 is a mutual inductance curve diagram of A1 and A2 provided in an embodiment of the present invention;

[0034] Figure 8 The A2 inverter provided in the embodiment of the present invention is not turned on C f2 Waveform of effective value of induced voltage at both ends;

[0035] Fig. 9 The A2 inverter provided in the embodiment of the present invention is turned on before and after C f2 The voltage waveform changes at both ends. DETAILED DESCRIPTION

[0036] The following specifically illustrates the implementation mode of the present invention in conjunction with the accompanying drawings. The embodiments are provided for illustrative purposes only and cannot be understood as limiting the present invention. The accompanying drawings are provided for reference and illustration only and do not constitute a limitation on the scope of patent protection of the present invention, because many changes can be made to the present invention without departing from the spirit and scope of the present invention.

[0037] The embodiment of the present invention provides a method for self-starting dynamic wireless charging of an electric vehicle based on position detection, such as Figure 1 As shown in the workflow diagram, the steps include:

[0038] S1. Determine the circuit structure and parameter design of the dynamic wireless charging system for electric vehicles;

[0039] This embodiment uses Figure 2 The circuit structure of the electric vehicle dynamic wireless charging system is shown as an example for explanation. Figure 2 As shown, the circuit structure includes a vehicle pickup end and multiple identical power transmitting ends, and the power transmitting end includes an inverter power supply, a primary compensation network, and a transmitting coil L p The vehicle pickup end includes a receiving coil, a secondary compensation network, a rectifier filter circuit, and a vehicle-end battery load R L ; The transmitting coils of multiple power transmitting ends are evenly laid along the road direction; In this embodiment, n identical transmitting coils A1, A2...A are evenly laid along the road direction n-1 , A n , where A1, A n For the first and last transmitting coils, A2…A n-1 It is the middle section transmitting coil.

[0040] S2, controlling the inverter power supplies of the first and last transmitting coils by phase shifting and voltage regulation to put the first and last transmitting coils in a low-power standby state, and controlling the inverter power supplies of the remaining transmitting coils to put the remaining transmitting coils in a closed state;

[0041] S3, detecting the inverter output current corresponding to the first transmitting coil and determining whether the current undergoes a first preset change, if so, turning on the first transmitting coil, if not, continuing to detect;

[0042] S4, detecting the induced voltage in the main circuit connected to the next transmitting coil and determining whether the voltage reaches the voltage threshold, if so, turning on the next transmitting coil, if not, continuing the detection;

[0043] S5, repeat step S4 until the tail section transmitting coil is turned on;

[0044] S6. Detect the inverter output current corresponding to the tail transmitting coil and determine whether the current undergoes a second preset change. If so, control the first and tail transmitting coils to resume a low-power standby state and turn off the remaining transmitting coils. Otherwise, continue detecting.

[0045] When the car is not in the dynamic wireless charging area, coils A1 and A n Through phase shifting and voltage regulation, it is in low power consumption standby mode, A2~A n-1 In the off state; after the car enters the charging area, the inverter output current of A1 changes, and it wakes up from the low-power standby state. When the car drives between the two adjacent transmitting coils A1 and A2, the energy transmitted from coil A1 to the receiving coil is partially reflected to coil A2. At the same time, the coupling between the adjacent rail coils on the ground section induces a voltage in the main circuit connected to them. By detecting the size of the induced voltage, the position of the electric car is determined and A2 is turned on in time, and so on; when the car gradually leaves the charging area, A n The inverter output current at the end changes, the middle transmitting coil is turned off, and the first and last coils return to standby state.

[0046] In this embodiment, if Figure 2 As shown, the inverter power supply is equipped with a DC power supply U dc The full-bridge inverter is built by switch tubes Q1, Q2, Q3 and Q4. Switch tubes Q1 and Q2 are connected to form the front half arm, and Q3 and Q4 are connected to form the rear half arm. The compensation network of the electric vehicle dynamic wireless charging system adopts a bilateral LCC structure, that is, both the primary compensation network and the secondary compensation network adopt an LCC structure. The primary compensation network includes the transmitting coil L p The primary inductor L in series f1 , and the transmitting coil L connected in series p 、Primary series capacitor C p1 The primary shunt capacitor C f1 The secondary compensation network includes the receiving coil L s The secondary inductor L in series f3 , and the receiving coil L connected in series s , the secondary side series capacitor C s The secondary shunt capacitor C f3 The rectifier and filter circuit includes a full-bridge rectifier composed of diodes D1 to D4 and a filter capacitor C d .

[0047] Under normal working conditions of the dynamic wireless charging system for electric vehicles, assuming that the working angular frequency of the inverter circuit is ω, the design of the structural parameters of the bilateral LCC compensation network must satisfy the following relationship:

[0048]

[0049] Considering the rectifier filter circuit, the equivalent impedance of the secondary loop can be expressed as:

[0050]

[0051] / / Indicates a parallel relationship.

[0052] The equivalent impedance reflected from the secondary side to the primary side is:

[0053]

[0054] M represents the transmitting coil L p and receiving coil L s The mutual induction between.

[0055] DC power supply U dc The high-frequency AC voltage source output after the high-frequency inverter circuit (full-bridge inverter) is U p , the primary side equivalent circuit is obtained as Figure 3 As shown. At this time, the primary side equivalent impedance is:

[0056]

[0057] The parameters of the electric vehicle dynamic wireless charging system in the present invention are shown in Table 1.

[0058] Table 1 System parameters

[0059] Parameter name Parameter Value <![CDATA[U dc ]]> 600V <![CDATA[L f1 ]]> 10μH <![CDATA[C f1 ]]> 350.6nF <![CDATA[C p1 ]]> 54.5nF <![CDATA[L p ]]> 75μH <![CDATA[L s ]]> 80.5μH <![CDATA[C s ]]> 189.5nF <![CDATA[C f3 ]]> 56.5nF <![CDATA[L f3 ]]> 18.5μH <![CDATA[R L ]]> 10.4Ω

[0060] In the full-bridge inverter, the drive signals of Q1 and Q2 are complementary, the drive signals of Q3 and Q4 are complementary, and the drive signal of Q3 lags behind Q1 by an angle θ (phase shift angle). p Perform Fourier decomposition to obtain the effective value of the kth harmonic at different phase shift angles:

[0061]

[0062] The wireless power transmission system is equivalent to a bandpass filter. Only the current near the fundamental frequency can produce resonance. The higher harmonics can be ignored and only the fundamental component is considered. When no car enters the charging coil area, the equivalent impedance on the inverter output side is only the primary impedance. The inverter output voltage amplitude is changed by phase shifting. The system is in a low-power standby state. The driving waveform of the switch tube is as follows: Figure 4 As shown. The phase shift angle of the low power standby state is θ1. In this embodiment, θ1 is set to 20°, so that the output voltage amplitude of the inverter is a preset value. When the vehicle enters the transmitting coil A1 area, due to the influence of the receiving end impedance reflected to the primary side, the equivalent impedance Z on the inverter output sideeq changes, so the effective value of the inverter output current also changes.

[0063] In the absence of a receiving coil, the inverter output current is 7.2A. In the case where the receiving coil is facing the transmitting coil, the inverter output current is 67.9A. The inverter voltage and current waveforms before and after the vehicle enters are as follows: Figure 5 , Figure 5 (a) is the waveform before entering. Figure 5 (b) is the waveform after the vehicle enters. As the secondary side gradually reaches the target position, the inverter output current gradually increases. Therefore, by sampling the inverter output, it is possible to determine whether the vehicle has entered, and then wake up the power transmitter. By adjusting the phase shift θ to θ2, the system starts to work normally.

[0064] As the electric car travels between the two transmitting coils A1 and A2, coil A1 is charged and in the energy transmission state, coil A2 is in the off state, and the vehicle-side receiving coil acts as a relay coil. Part of the energy transferred from A1 to the receiving coil is reflected to the transmitting coil A2. During the travel, its electromagnetic coupling with the transmitting coil A1 continues to weaken, and its electromagnetic coupling with the transmitting coil A2 continues to strengthen; at the same time, there is also electromagnetic coupling between the adjacent transmitting coils A1 and A2 on the ground side, thereby inducing high-frequency voltage and current in the main circuit connected to A2. At this time, the system can be equivalent to a single-transmitter-multiple-pickup circuit topology model, such as Figure 6 shown.

[0065] According to Kirchhoff's voltage and current laws, the loop equation for loop 1 is:

[0066]

[0067] The loop equation for loop 2 is:

[0068]

[0069] The loop equation for loop 3 is:

[0070]

[0071] The loop equation for loop 4 is:

[0072]

[0073] The loop equation for loop 5 is:

[0074]

[0075] From equations (3)-(6), it can be obtained that when coil A1 is turned on, the induced current in coil A2 is:

[0076]

[0077] Capacitor C f2 The induced voltage across the two ends is:

[0078]

[0079] SIMULINK is used to build a LCC-LCC topology electric vehicle dynamic wireless charging simulation model to simulate the process of an electric vehicle driving through two adjacent coils A1 and A2, each with a length of 150 cm. In the COMSOL finite element simulation software, the mutual inductance between A1 and the receiving coil, the mutual inductance between A2 and the receiving coil, and the mutual inductance curve between A1 and A2 are obtained during this driving process, as shown in Figure 7 As shown. Figure 7 It can be clearly seen that when the vehicle pickup end moves, the change in coupling strength between the two adjacent transmitting coils is weaker than that between them and the pickup coil, and the mutual inductance between the receiving coil and the two coils keeps changing.

[0080] Different mutual inductance values ​​represent different positions of the vehicle pickup end. After coil A1 is turned on, without turning on coil A2, coil A2 induces high-frequency voltage and current in the main circuit to which it is connected. Through simulation, C f2 The waveform of the effective value of the induced voltage at both ends is as follows: Figure 8 shown.

[0081] The voltage threshold should be determined based on the pre-calibrated steady value and maximum value of the voltage sensed by the next section of the transmitting coil during the process from the previous section of the transmitting coil that is turned on to the end of the next section of the transmitting coil that is not turned on. If the voltage threshold is set too high, it is easy for the system to fail to detect the position of the vehicle end coil, resulting in the inverter being unable to open in time; if the voltage threshold is too low, the anti-interference ability of the position detection system will be reduced. Based on the above considerations, let U th Indicates the voltage thresholds, U0 and U m They represent the stable value and the maximum value sensed by the next transmitting coil, respectively. In this embodiment, the voltage threshold U th The setting principle is U0+(U m -U0) / 4≤U th ≤U m -(U m -U0) / 2.

[0082] observe Figure 8 From the waveform shown, it can be determined that the stable value is about 550V and the maximum value is about 566V, so the voltage threshold should be selected between [554,558]. thSet to 554V, and use this voltage threshold as the control signal for switching the transmitting coil. Once the induced voltage of the next transmitting coil reaches the voltage threshold U th , that is, control the next section of transmitting coil to open.

[0083] Take the process of turning on coil A2 as an example. When the receiving coil is just located above coil A1, the voltage across the parallel resonant compensation capacitor in the coil A2 circuit does not reach the threshold and remains in the off state. When its value flows through the comparison circuit and reaches the set voltage threshold, the inverter of coil A2 is turned on. After turning on, C f2 The voltage variation curve at both ends is as follows Fig. 9 At this time, it is still 25cm away and enters the A2 area, which is beneficial to the stability of the power received by the vehicle.

[0084] Furthermore, the opening conditions for the subsequent lth coil are the same as the above analysis. As the car gradually drives away from the last coil A n That is, the tail section transmitting coil, coil A n The inverter output current value in the circuit gradually decreases. When the value is equal to the inverter output current value without the receiving coil, it can be judged that the car has completely left, and all the middle transmitting coils are turned off. The first and last coils return to the standby state and wait for the next vehicle to enter the road.

[0085] The embodiment of the present invention further provides an electric vehicle dynamic wireless charging self-starting system based on position detection, which applies the above-mentioned electric vehicle dynamic wireless charging self-starting method based on position detection, and is provided with an inverter power supply control module, an inverter output current detection module, and an induced voltage detection module;

[0086] The inverter power supply control module is used to control the inverter power supplies of the first and last transmitting coils through phase shifting and voltage regulation to put the first and last transmitting coils in a low-power standby state, and control the inverter power supplies of the remaining transmitting coils to put the remaining transmitting coils in a closed state;

[0087] The inverter output current detection module is used to detect the inverter output current corresponding to the first section transmitting coil and send it to the inverter power control module; the inverter power control module is also used to determine whether the inverter output current sent by the inverter output current detection module undergoes a first preset change, if so, the first section transmitting coil is turned on, otherwise, the detection continues; the induced voltage detection module is used to detect the induced voltage in the main circuit connected to the next section transmitting coil and send it to the inverter power control module; the inverter power control module is also used to determine whether the induced voltage sent by the induced voltage detection module reaches a voltage threshold, if so, the next section transmitting coil is turned on, otherwise, the detection continues; the inverter output current detection module, the inverter power control module, and the induced voltage detection module repeat the process until the induced voltage detection module turns on the last section transmitting coil;

[0088] The inverter output current detection module is also used to detect the inverter output current corresponding to the tail section transmitting coil after the tail section transmitting coil is turned on and send it to the inverter power supply control module; the inverter power supply control module is also used to determine whether the inverter output current corresponding to the tail section transmitting coil sent by the inverter output current detection module undergoes a second preset change. If so, the first and tail section transmitting coils are controlled to resume the low power standby state and turn off the remaining transmitting coils. Otherwise, the detection continues.

[0089] In summary, the electric vehicle dynamic wireless charging self-starting method and system based on position detection provided by the embodiment of the present invention can determine whether the vehicle enters and leaves the charging area by detecting the difference in the inverter output current of the first and last transmitting coils in the absence of receiving coils and with receiving coils. The determination can be completed by only detecting the inverter output current; for the subsequent transmitting coils, the induced voltage generated by the coupling between the coils is used to compare the threshold value and then turn it on. The method and system can accurately locate the electric vehicle and realize the precise control and switching of the transmitting coil, thereby ensuring the high reliability of the system, and does not add additional detection devices. It is easy to operate and can significantly reduce the complexity and cost of the system, achieving the purpose of effectively saving energy and realizing precise charging.

[0090] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A method for self-starting dynamic wireless charging of electric vehicles based on position detection, characterized in that: Includes steps: S1. Determine the circuit structure and parameter design of the dynamic wireless charging system for electric vehicles; The circuit structure includes a vehicle pickup end and a plurality of identical power transmitting ends, wherein the power transmitting end includes an inverter power supply, a primary compensation network, and a transmitting coil; the vehicle pickup end includes a receiving coil, a secondary compensation network, a rectifier filter circuit, and a vehicle-end battery load; the transmitting coils of the plurality of power transmitting ends are evenly laid along the road direction; S2, controlling the inverter power supplies of the first and last transmitting coils by phase shifting and voltage regulation to put the first and last transmitting coils in a low-power standby state, and controlling the inverter power supplies of the remaining transmitting coils to put the remaining transmitting coils in a closed state; S3, detecting the inverter output current corresponding to the first transmitting coil and determining whether the current undergoes a first preset change, if so, turning on the first transmitting coil, if not, continuing to detect; S4, detecting the induced voltage in the main circuit connected to the next transmitting coil and determining whether the voltage reaches the voltage threshold, if so, turning on the next transmitting coil, if not, continuing the detection; S5, repeat step S4 until the tail section transmitting coil is turned on; S6. Detect the inverter output current corresponding to the tail transmitting coil and determine whether the current undergoes a second preset change. If so, control the first and tail transmitting coils to resume a low-power standby state and turn off the remaining transmitting coils. Otherwise, continue detecting.

2. The electric vehicle dynamic wireless charging self-starting method based on position detection according to claim 1 is characterized in that: The inverter power supply is provided with a full-bridge inverter constructed by switch tubes Q1, Q2, Q3 and Q4, wherein the switch tubes Q1 and Q2 are connected to form a front half arm, and Q3 and Q4 are connected to form a rear half arm; In step S2, the inverter power supply of the first and last section transmitting coils is controlled by phase shifting and voltage regulation to put the first and last section transmitting coils in a low power consumption standby state, specifically: The driving signals of the switch tubes Q1 and Q2 of the full-bridge inverter controlling the first and last transmitting coils are complementary, and the driving signals of Q3 and Q4 are complementary. The driving signal of Q3 lags behind Q1 by an angle θ1, so that the output voltage amplitude of the inverter is a preset value.

3. The electric vehicle dynamic wireless charging self-starting method based on position detection according to claim 1 is characterized in that: In the step S3, the first preset change is that the inverter output current corresponding to the first section of the transmitting coil increases from the output current in the case where there is no receiving coil.

4. The electric vehicle dynamic wireless charging self-starting method based on position detection according to claim 1 is characterized in that: In step S4, the voltage threshold is determined according to the pre-calibrated steady value and maximum value of the voltage sensed by the next transmitting coil during the process of the vehicle pickup end traveling from the previous transmitting coil that is turned on to the end of the next transmitting coil that is not turned on.

5. The electric vehicle dynamic wireless charging self-starting method based on position detection according to claim 4 is characterized in that: Let U th Indicates the voltage thresholds, U0 and U m They represent the stable value and the maximum value of the voltage sensed by the next transmitting coil, respectively. The voltage threshold is set as U0+(U m -U0) / 4≤U th ≤U m -(U m -U0) / 2.

6. The electric vehicle dynamic wireless charging self-starting method based on position detection according to claim 5 is characterized in that: In the step S6, the second preset change is when the inverter output current corresponding to the tail section transmitting coil begins to gradually decrease until it is equal to the inverter output current value when there is no receiving coil.

7. The electric vehicle dynamic wireless charging self-starting method based on position detection according to claim 2 is characterized in that: The transmitting coil is turned on by adjusting the phase shift angle θ of the full-bridge inverter of the transmitting coil to θ2.

8. An electric vehicle dynamic wireless charging self-starting system based on position detection, the system applying an electric vehicle dynamic wireless charging self-starting method based on position detection according to any one of claims 1 to 7, characterized in that: The system is equipped with an inverter power supply control module, an inverter output current detection module, and an induced voltage detection module; The inverter power supply control module is used to control the inverter power supplies of the first and last transmitting coils through phase shifting and voltage regulation to put the first and last transmitting coils in a low-power standby state, and control the inverter power supplies of the remaining transmitting coils to put the remaining transmitting coils in a closed state; The inverter output current detection module is used to detect the inverter output current corresponding to the first section transmitting coil and send it to the inverter power control module; the inverter power control module is also used to determine whether the inverter output current sent by the inverter output current detection module undergoes a first preset change, if so, the first section transmitting coil is turned on, otherwise, the detection continues; the induced voltage detection module is used to detect the induced voltage in the main circuit connected to the next section transmitting coil and send it to the inverter power control module; the inverter power control module is also used to determine whether the induced voltage sent by the induced voltage detection module reaches a voltage threshold, if so, the next section transmitting coil is turned on, otherwise, the detection continues; the inverter output current detection module, the inverter power control module, and the induced voltage detection module repeat the process until the induced voltage detection module turns on the tail section transmitting coil; The inverter output current detection module is also used to detect the inverter output current corresponding to the tail section transmitting coil after turning on the tail section transmitting coil and send it to the inverter power supply control module; the inverter power supply control module is also used to determine whether the inverter output current corresponding to the tail section transmitting coil sent by the inverter output current detection module undergoes a second preset change. If so, the first and tail section transmitting coils are controlled to resume the low power standby state and turn off the remaining transmitting coils. Otherwise, the detection continues.

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